EVGA BQ850 Three 8-pin PCI-e plugs and three 6-pin plugs. Need 4 8-pins.

[Xenohitsu]

I bought two AMD Vega 56 GPUs which requires two 8 pin connectors each. My EVGA BQ850 PSU has three 8-pin plugs and three 6 pin plugs. I have three remaining 6-pins that aren't being used from the single rail. Is it possible to convert them into one extra 8-pin so I have four? Card: https://www.newegg.com/Product/Product.aspx?Item=N82E16814126186. This adapter apparently converts two 6 pin into an 8 pin, http://www.ebay.com/itm/PCI-E-8pin-...150622?hash=item4b20c2485e:g:rkYAAOSwmo5ZnSLB Would that work? Regarding power consumption, the Vega 56 peaks around 237 watts each, and I calculated 850watt should be enough as I don't plan on overclocking and I'm more concerned with it running right now with all 8-pins than reaching the power supply's limit. Currently Crossfire is not supported, so this might not be possible, but I bought a second one in case it is supported sometime.

There is also a 6-pin to 8-pin adapter that sells many units on eBay, but i'm skeptical of it because i do not know how the power is delivered http://www.ebay.com/itm/332247542151 (usually only more to less, or perhaps better guage wire?)

Thanks in advance!

Edit 2: MSI includes a 6-pin to 8-pin adapter, so I guess I am all set now, fortunately!

Edit: I realize only one of the three 6-pins originate from a separate cable from the power supply. The other two are split ends of the 8-pin cables from the modular pci-e plugs on the PSU. So i am figuring maybe a six-pin to 8-pin adapter might work, if that is ok.

 

[S_I_N]

I'm not sure if 2 vegas will work on a 850 watter, despite what a psu calc said. Specially when the specs say min 750watts needed for a single (yes this includes the rest of the system. That being said there is currently no support for crossfire with vega as of now. Its disabled by AMD.

 

[Xenohitsu]

I'm not sure if 2 vegas will work on a 850 watter, despite what a psu calc said. Specially when the specs say min 750watts needed for a single (yes this includes the rest of the system. That being said there is currently no support for crossfire with vega as of now. Its disabled by AMD.

You might be right about Crossfire support, but I currently use a 620watt Seasonic MII 12 Evo that runs fine on a single Vega 56. Guru3D did a benchmark, and tested only 236 from the PCI-e slot. http://www.guru3d.com/articles_pages/amd_radeon_rx_vega_56_8gb_review,30.html
Toms Hardware uses a more sensitive meter: http://www.tomshardware.com/reviews/radeon-rx-vega-56,5202-21.html I am not sure whether the absolute peak of 376.4 was calculated from an overclocked one, though I could switch to BIOS 2 if CFX becomes to close to the limit. 376 watts for 50ms theoretically could peak at the same time on each card and not be enough for the 840 watt limit, assuming 100% cpu utilization. 258watts x2 seems ideal at max load once in a while (Turbo Bios 1)

My Saphhire box & website recommends 650, so yes, my PSU is a little lightweight, but i use a 95watt CPU instead of a 125-140watt one. http://www.sapphiretech.com/productdetial.asp?pid=7F02806A-E92D-4787-B200-7BCC877B6E9B&lang=eng I've also benchmarked 3D Mark Firestrike Ultra and Metro 2033 Last Light on Max Settings at 4k resolution (including PhysX and SSAA and Tesselations) without a hiccup.

I plan to install the 850 watt supply if/when CFX is supported. Otherwise I might sell the Vega.

 

[EarthDog]

Clearly a 750w psu isnt needed for this card....those recommendations always are well over what is needed.

850w is plenty for CF which isnt really supported as mentioned before.

 

[Sentential]

You might be right about Crossfire support, but I currently use a 620watt Seasonic MII 12 Evo that runs fine on a single Vega 56. Guru3D did a benchmark, and tested only 236 from the PCI-e slot. http://www.guru3d.com/articles_pages/amd_radeon_rx_vega_56_8gb_review,30.html
Toms Hardware uses a more sensitive meter: http://www.tomshardware.com/reviews/radeon-rx-vega-56,5202-21.html I am not sure whether the absolute peak of 376.4 was calculated from an overclocked one, though I could switch to BIOS 2 if CFX becomes to close to the limit. 376 watts for 50ms theoretically could peak at the same time on each card and not be enough for the 840 watt limit, assuming 100% cpu utilization. 258watts x2 seems ideal at max load once in a while (Turbo Bios 1)

My Saphhire box & website recommends 650, so yes, my PSU is a little lightweight, but i use a 95watt CPU instead of a 125-140watt one. http://www.sapphiretech.com/productdetial.asp?pid=7F02806A-E92D-4787-B200-7BCC877B6E9B&lang=eng I've also benchmarked 3D Mark Firestrike Ultra and Metro 2033 Last Light on Max Settings at 4k resolution (including PhysX and SSAA and Tesselations) without a hiccup.

I plan to install the 850 watt supply if/when CFX is supported. Otherwise I might sell the Vega.

I'm in the same boat as you considering a similar setup and I believe overclocking aside 850W should be enough although I am debating getting a 1kw for the possible dual Vega 11 boards that are supposedly going to launch next year (Vega 11 = RX680?/Vega32 not Vega56/64). The 620W seasonic you have should be enough to skate by my only recommendation would be to use the secondary BIOS. The primary BIOS (position rear towards exhaust) sets board power to 220W where as the secondary BIOS (position forward pointing towards the power plugs) limits board power to 200W. If you set both to the secondary BIOS I don't see any reason why you couldn't use the 620W you have now with dual-Vega.

I saw the Tom's article as well my understanding is that the absolute peak they are calculating is for what the card could use as a maximum, meaning 75W from the PCI-E slot plus 150W 8-pin plus 150W 8-pin. So it's not actually drawing 376W it just that it COULD draw 376W.

My plan is to mine until either Xfire is supported or the cards are paid off and I can make a decision from there.

 

[S_I_N]

I'm sorry but as a pc enthusiast and card carrying member of the PC Master Race lol. I'd want to cover the could draw scenario, wont be alot of fun if the could draw part hit in the middle of a massive gaming session, the powers not there so my rig shuts down. Its been rule #1 for ages in the pc building realm (DONT CHEAP OUT ON TH PSU). So again my recommendation is to buy the best you can afford and since you have tyhe $$ for 2 vegas, I'm assuming a quality proper wattaged psu can be easily obtained. And also seeing as your current unit does not have the hookups you need (in my head it says iy cant do 4 8pins) then buying a proper one that have the needed 4 8 pin pci-e you need is also a smarter choice, instead of trying to Frankenstein it with adapters.

 

[EarthDog]

You have the could draw scenario covered twice over on your PC...

850W PSU is plenty for two cards, including overclocking. If he does it right, undervolts and overclocks as these can, a 750W would be good.

I whole heartedly agree on getting a QUALITY PSU that has the necessary connections for the money. But, there isn't a need to overbuy.

 

[Xenohitsu]

You have the could draw scenario covered twice over on your PC...

850W PSU is plenty for two cards, including overclocking. If he does it right, undervolts and overclocks as these can, a 750W would be good.

I whole heartedly agree on getting a QUALITY PSU that has the necessary connections for the money. But, there isn't a need to overbuy.

I had already bought the EVGA 850 PSU recently after finding it for $60 refurbished on Newegg- product specs: https://www.evga.com/Products/Product.aspx?pn=110-BQ-0850-V1 There are many peripheral plugs that are going unused, with only one HDD, thus I conclude 850w will suffice.

I prefer my Seasonic over EVGA, though I bought the Vega 56 since it was a cheaper option than the Vega 64, and I'm hesitant to further reduce performance by switching to BIOS 2, although I agree that since I had the money to buy two Vegas I should be able to buy a quality PSU. I have the unfortunate habit of calculating a minimum power need, then buying a power supply on sale, then buying another one with slightly more power. So I have 4 power supplies- 330w, 520w, 620w, and 850w; the first three are Seasonic. If I skipped the 520 and 620, I'd have a Seasonic 850. But the reviews for the EVGA were acceptable and I don't plan to overclock. Though I plan to test it first on older system just to make sure it can handle gaming load. http://www.tomshardware.com/reviews/evga-bq-series-850w-psu,4842.html

 

[Xenohitsu]

I'm in the same boat as you considering a similar setup and I believe overclocking aside 850W should be enough although I am debating getting a 1kw for the possible dual Vega 11 boards that are supposedly going to launch next year (Vega 11 = RX680?/Vega32 not Vega56/64). The 620W seasonic you have should be enough to skate by my only recommendation would be to use the secondary BIOS. The primary BIOS (position rear towards exhaust) sets board power to 220W where as the secondary BIOS (position forward pointing towards the power plugs) limits board power to 200W. If you set both to the secondary BIOS I don't see any reason why you couldn't use the 620W you have now with dual-Vega.

I saw the Tom's article as well my understanding is that the absolute peak they are calculating is for what the card could use as a maximum, meaning 75W from the PCI-E slot plus 150W 8-pin plus 150W 8-pin. So it's not actually drawing 376W it just that it COULD draw 376W.

My plan is to mine until either Xfire is supported or the cards are paid off and I can make a decision from there.

620w for both Vegas on BIOS2 sounds like a great idea! If my EVGA BQ 850watt PSU stops working without damaging any of my components for whatever quality inferiority it has over the Seasonic, I'll use the 620watt. I use the 620watt for one Vega 56 since the drivers still don't support CFX. I suppose I could flash the bios to Vega 64 (sans extra shaders) and buy a 950 watt PSU to get a 15% improvement but I'm hesitant to increase the temperature. Check out my 3dmark scores: https://www.3dmark.com/spy/2412176 https://www.3dmark.com/fs/13667568

https://www.3dmark.com/fs/13667544

About 4 years ago, I would underclock my Radeon 7950 to 700mhz on a 330watt Seasonic PSU. The worst that would happen was that the PC shutdown immediately. It didn't happen often at 700Mhz, but at stock 1000Mhz it would. A handful of times near 700 it would too, but not nearly as often. It was tolerable to get through a few games that I played. Everything worked after I powered it back on.Hopefully the same can be said of EVGA.

 

[Sentential]

620w for both Vegas on BIOS2 sounds like a great idea! If my EVGA BQ 850watt PSU stops working without damaging any of my components for whatever quality inferiority it has over the Seasonic, I'll use the 620watt. I use the 620watt for one Vega 56 since the drivers still don't support CFX. I suppose I could flash the bios to Vega 64 (sans extra shaders) and buy a 950 watt PSU to get a 15% improvement but I'm hesitant to increase the temperature. Check out my 3dmark scores: https://www.3dmark.com/spy/2412176 https://www.3dmark.com/fs/13667568

Here are mine for a comparison, note that his was a genuine bench run with fan @ 100% and max clocks 1573/960:
https://www.3dmark.com/spy/2368391
https://www.3dmark.com/fs/13597935

I think you should be OK on BIOS2 it really doesn't drop performance all that much. I'll give an example I am currently mining on my graphics amplifier to offset the cost on BIOS2. With -20% offset and my current clocks as reported by GPUz are 1209 / 955 with 118W. With that I'm putting out 34.673 -> 35.087MH/s. Current temps read: 64C* GPU, 68C* Hotspot, 77C* HBM @ 1826RPM (targeted 65C*) this was repasted with Conductonaut Liquid Metal as I have a sealed-epoxied die package. So my temps are spot on, noise is non-existent and I'm bang on for hashrate. Once I've made my quota I'm going to switch back to balanced and leave it at that until BIOS modding becomes available at which point I'll bump default HBM speeds to 925 and call it a day.

It's up to you whether you want to try overclocking Vega, I personally am unsure whether it's worth it as its already quite good and since I am using mine for virtualization training I don't see much of a need to push it.

My next planned build is going to be a Hypervisor server:
Ryzen APU (going Bristol Ridge for now, Raven later)
64GB RAM
RAID6 Array with spinny drives
NVME primary OS (Toshiba XG3)
850 or 1000w PSU haven't decided.

I haven't decided on GPUs yet either hence my initial reply. I might buy one more RX Vega56 and transfer both to the HV machine and LM paste the 2nd one, or maybe a pair of RX580s until Vega 11 duals come around, not sure. Going to mine on this one as well and the APU should help. This one I'll probably abuse and overclock heavily again to try and recoup the cost of my Hypervisor machine. Since the company hasn't (as far as I know) chosen a direction on what OS domain2.0 is going to launch on so I know which certificate to go for.

 

[Xenohitsu]

Here are mine for a comparison, note that his was a genuine bench run with fan @ 100% and max clocks 1573/960:
https://www.3dmark.com/spy/2368391
https://www.3dmark.com/fs/13597935

wow, yours got 15,000 on Firestrike whereas I got 9,000 https://www.3dmark.com/fs/13667544 . My TimeSpy is only around 1,000 less than yours though

 

[Dolk]

Hey Xen, I'm a Vega 64 owner and I've been monitoring that Vega thread on OCN for a long time. I learned a lot for those guys doing most of the experimenting.

One of the first things that people discovered was the power hog that Vega's are. The best setup for the Vega is to use individually sourced 8-pin PCI-E power pins. That means not using the extra 8-pin that is connected to the same break-out. Daisy Chaining does not supply enough current for the Vega's can hinder performance.

850W PSUs have also been proven not to be very effective in powering these cards. AMD has come out and recommended 1000W PSUs while running these cards. It is not the constant power draw that will kill your PSU its the quick power transistions. You will see the card go from 10W idle to 250W+ in quick successions depending on what you are doing. Heavy power draws can break a PSU easily. So just be aware of that when you are running your minning. Best practice is to underclock and reduce the total power for these cards.

 

[Xenohitsu]

Hey Xen, I'm a Vega 64 owner and I've been monitoring that Vega thread on OCN for a long time. I learned a lot for those guys doing most of the experimenting.

One of the first things that people discovered was the power hog that Vega's are. The best setup for the Vega is to use individually sourced 8-pin PCI-E power pins. That means not using the extra 8-pin that is connected to the same break-out. Daisy Chaining does not supply enough current for the Vega's can hinder performance.

850W PSUs have also been proven not to be very effective in powering these cards. AMD has come out and recommended 1000W PSUs while running these cards. It is not the constant power draw that will kill your PSU its the quick power transistions. You will see the card go from 10W idle to 250W+ in quick successions depending on what you are doing. Heavy power draws can break a PSU easily. So just be aware of that when you are running your minning. Best practice is to underclock and reduce the total power for these cards.

Thanks Dolk, I understand that is for the Vega 64 and likely would impact the Vega 56 to some degree. I realize the Vega 56 has several power profiles-two bioses and energy saving profiles. i haven't done any overclocking and the Vega 64s use around 295 watts, whereas the Vega 56 is locked around 220watts, as Sentinal as mentioned. I definitely appreciate the info on the 8-pin power connectors-I realize the 850watt might be insufficient, so I will definitely be careful if I choose to use that one.

Edit: Can you link me to the Vega thread you were referring to ?

 

[EarthDog]

850W PSUs have also been proven not to be very effective in powering these cards. AMD has come out and recommended 1000W PSUs while running these cards.

Links please! I do not want to share misinformation...

He also has two 56, not 64s... does that temper your 1KW suggestion?

 

[Dolk]

OCN Vega Thread:
http://www.overclock.net/t/1634018/official-vega-frontier-rx-vega-owners-thread

User talking about how his breaker tripped using Vega:
http://www.overclock.net/t/1634018/official-vega-frontier-rx-vega-owners-thread/210#post_26288377

User talking about PowerPlay can easily wipe out your 850W PSU:
http://www.overclock.net/t/1634018/official-vega-frontier-rx-vega-owners-thread/220#post_26288514

Xen, the 56 can be overclocked a lot once you start to mod the registers. The Vega has an encrypted BIOS so BIOS mods will be limited for a long time. However, you can do some neat tricks to get more out of it. I've been busy compiling information and testing out my own system for long term stability before posting a guide. Plus I wanted to see AMD drivers improve before putting this info up.

EDIT

ED, Didn't see that question at first. I'd say kinda... Although the 56s are lower in power, he is drawing more with two than a single 64.

 

[EarthDog]

Thanks man!

Last link says this bolded the important parts:

Vega 64 air here, did powerplay table reg mod to allow for +100% PL, which triggered the OCP on my HX850i when loading 3DMark Timespy for example. Had to swap out the psu for the old RM1000, seing max sustained power draw at the psu of about 550W (oc'd Ryzen 7 system).

The guy modded it for double the PL... You are spot on if this person plans to modify his card to push DOUBLE its output...

2nd link.. if he tripped a breaker with a single card, sounds like his house needs rewired and the breaker checked to me....the post even said his PSU was likely going out if that happened.. Zero mention of what he was doing there either...

Not sure this helped convince me of anything, considering........

 

[Dolk]

There are a lot of pages in that thread, but other users have mentioned issues. it could be just luck in the data set and each person has some other issue outside of drawing a ton from their sub 1K PSU.

However, the point is that if you plan on using these cards, make sure you don't skimp on the PSU. Its going to be stressed, and the more use these cards, the harder its going to be on the PSUs. 850W may work for now but will it last? Time will tell. Cards have only been out for a month or so.


BTWWW, news came in, 17.9.2 is coming in soon with Xfire support for Vega.

 

[Xenohitsu]

There are a lot of pages in that thread, but other users have mentioned issues. it could be just luck in the data set and each person has some other issue outside of drawing a ton from their sub 1K PSU.

However, the point is that if you plan on using these cards, make sure you don't skimp on the PSU. Its going to be stressed, and the more use these cards, the harder its going to be on the PSUs. 850W may work for now but will it last? Time will tell. Cards have only been out for a month or so.


BTWWW, news came in, 17.9.2 is coming in soon with Xfire support for Vega.

Thanks Dolk I just saw that too: http://www.overclock.net/t/1634018/official-vega-frontier-rx-vega-owners-thread/2210#post_26351744 Perfect timing!

Thanks Dolk I just saw that too: http://www.overclock.net/t/1634018/official-vega-frontier-rx-vega-owners-thread/2210#post_26351744 Perfect timing!

Edit: just found article on CFX: http://www.guru3d.com/news-story/amd-enables-rx-vega-mgpu-support-with-radeon-software-17-9-2.html

 

[EarthDog]

There are a lot of pages in that thread, but other users have mentioned issues. it could be just luck in the data set and each person has some other issue outside of drawing a ton from their sub 1K PSU.

However, the point is that if you plan on using these cards, make sure you don't skimp on the PSU. Its going to be stressed, and the more use these cards, the harder its going to be on the PSUs. 850W may work for now but will it last? Time will tell. Cards have only been out for a month or so.


BTWWW, news came in, 17.9.2 is coming in soon with Xfire support for Vega.

Sorry, I know I am being difficult here, but, the others that have had issues, are htey modifying their PLs too? The link clearly stated that guy modified the power tables to accept double the amount of power (on a 64 no less).

Nobody is saying to skimp. 850W should be plenty considering the information on power draw in reviews and such. If Xen is modifying the BIOS, this is great information. If not, I still believe an 850W PSU is plenty for two V56...

 

[Dolk]

I get that ED, I however like to play on the cautious side. When more than 50% of your PSU is being dedicated to a single subsystem, you are going to want to balance.

And yes, not enough information is given by these posters. A lot of them are just general complaints with no background as to what caused their issue. It's always good to be aware of these issues as they can be the first part of diagnosing any future troubles someone may have.