Amazing Zosma!

[trents]

Got my PII 960T a few days ago and just finished my overclock. I'm very impressed with this CPU! There just can't be a CPU out there with a better performance to price ratio. This is the second build I've done with the Zosma and I'm even more impressed than I was after the first one. The first one was for my daughter and I managed to get it to 4.0 ghz on five cores with an old TRUE cooler and an ASRock 870 Extreme 3 motherboard. Core #5 was defective so I disabled it.

This time around I got one with six viable cores and on just under 1.5 vcore it's Prime95 stable at 3.8 ghz with estimated core temps in the mid 30s C. range. I say estimated because when you unlock cores, as most of you know, you lose the core temp read and have to rely on CPU temp. I did check the differential between core temp and CPU temp before unlocking the cores. The differential was 22 C. and since idle core temps were sub ambient I added 10 C. to the core temp as an offset. CPU temps under load maxed out at 57 C. so I did the math and subtracted about 10 C. from that number to get the core temp estimate. That's where I got mid 30s C. for the core temp and it may be a conservative number. This is on air cooling with a Corsair A70 push pull and fans on low speed.

CPU settings: 19x/1.48 vcore 6 cores
FSB: 200 mhz
CPUNB: 2600 mhz/1.225v
HT Link: 2200 mhz/stock voltage
Ram: running at 1600 mhz using the recommended XMP timings on 1.55v

In case you're wondering, as a four core I got it to 4.1 ghz on just under 1.5 max vcore with temps about 5-6 C. cooler than as a six core at the 3.8 ghz frequency I spoke of above.

I am reasonably certain I could have squeezed a little more out of it both as a four core and a six core if I had been willing to push the vcore envelope more. But my motherboard is not a top drawer enthusiast product (board sinks were starting to get a little warm) and I intend to run this thing 24/7 with these frequencies and voltages so I'm playing it more conservatively than some people might. All information in my sig is current if you care to reference it.

My observations about this CPU:

1. Runs quite cool and the frequency scales quite well with the vcore when overclocking. I didn't get the sense of hitting the wall suddenly like you do with many CPUs that give you a certain amount of overclock with modest voltage increases but only give that one more increment of speed with a lot more voltage. With the Zosma, the wall seems to come at you gradually. I attribute that to the E0 stepping and this being a mature product.
2. Sold as a four core at a quad price but will almost always unlock one core and often times give you two viable unlocked cores.

Get one while they're still being produced!

 

[RGone]

Good results man it seems. Nice report on how and what it took to go there. Have fun and enjoy.

RGone...ster.________________________

 

[rescuetoaster]

Yeah, this cpu is pretty damned amazing. I got mine as a gift for xmas, but it was 110 dollars at the time! I'm also at 3.8, and I am going to be (finally) taking her to 4.0 tonight since I have some time to stress test it.

 

[midlight21]

Yes, so far I love mine. I'm currently at 4 x 3.4 for now. Will go higher when I have the chance to work it out. Mine unlocks to 6 cores too.

 

[trents]

In case anyone's wondering about how unlocking cores affects TDP, I have a watt meter and I can give you some hard figures. The watt meter goes between the wall socket and the PSU 120v power cord so it measures total system power draw.

Under load, my 960T unlocked to 6 cores at 3.8 ghz on a vcore of 1.48 produces a heat load equivalent to around 150 watts. This is the differential between total wattage of the system when the Windows CPU activity gadget meter shows no activity and total wattage of the system when the CPU is under Prime95 100% load. Under those same conditions HWMonitor rates the CPU at 177 watts TDP and CPU-z rates it at 161 TDP. So it seems CPU-z is more accurate than HWmonitor in this category but both estimate TDP on the high side.

I thought this might help answer some questions about the accuracy of software TDP estimates. I also thought this might shed some light about whether or not unlocking cores that may (or may not) be out of spec results in disproportionate extra power draw compared to a CPU from the same family sold with no locked (and supposedly, no out of spec) cores. I would think that say a 125W TDP X6 1055 Thuban overclocked to the same level as my Zosma would probably be making 25 extra watts of power, wouldn't you?

 

[trents]

I found this very interesting and confirms what I was saying about the Zosma' price to perfromance ratio and value: http://www.cpubenchmark.net/cpu.php?cpu=AMD+Phenom+II+X4+960T (Second graph)

Of course, this was in a non-overclocked, non-unlocked state. When you unlock cores it really separates from the pack.

 

[rescuetoaster]

Thank you for posting that about the TDP, I've always wondered if that is an issue or not. So, would you say it's not a big deal to run it at this state then? My 970a-UD3 is rated for 140 TDP I believe.

Also, as an update, I could not get to 4.0 last night. I ran at 3.9 for an hour using blend, but right when I told it to stop all jobs it blue screened. I had multiplier set to 19 (1.4 volt), CPU-NB at 2600 (1.225 volt), and HT at 2200 (default volt).

 

[trents]

I had to set my vcore to 1.475 in bios with LLC on Auto to be stable at 19x on six cores.

 

[rescuetoaster]

So with the load line calibration thing, how high does your vcore jump to when you are stressing it? Mine will jump to about 1.48 at its highest when I have vcore set to 1.4

 

[trents]

That's exactly what mine jumps too as well when I set my vcore to 1.475. I'm looking at the Zalmann 9700 cooler and I have my doubts as to whether you can go that high with the vcore, safely, that is. Have you checked for temps with that vcore setting?

 

[mjw21a]

It's funny how many people have bought and truly love this platform considering the bad press they got at release. I think people just expected too much.

 

[rescuetoaster]

Well if my calculations are correct, the core temp should be about 42 to 44 since the socket temp ran about 8 or 9 degrees higher than the core temp when I tested it as a quad core.

 

[Neuromancer]

It's funny how many people have bought and truly love this platform considering the bad press they got at release. I think people just expected too much.

Zosma didnt get a lot of bad press, its a cut down thuban. It got some but not like Bulldozer.

 

[keny]

I have also found that these chips will scale to crazy NB levels, 3000 does not seem like a major hurdle with the right, seemingly low CPU NB of 1.25, plus they can handle a higher memory clock of almost 2000 which is almost impossible on a Deneb(unless you're really lucky), It's good to know about the TDP (thanks Trents), when I first unlocked it I saw the TDP figure and nearly fell of my chair, instantly checking the boards sinks for heat, but it seems you're calculations have disproven the high amount, even after overclocking, it's still lower than the quoted TDP, which is a nod to give it even more vcore

Edit : By the way! Check my sig to show how good these chips are
Edit 2 : Where has my sig gone ?

 

[trents]

So I switched back to four core mode at 4.1 ghz to get my TDP back down below the motherboard's rating of 140 TDP. On six cores at 3.8 it was pulling about 150W. Snappier at 4.1 as well, as you would expect since the extra cores weren't being used anyway. On four cores with the overclock its pulling about 115W according to my in line watt meter and HWMonitor says 118 so the program is pretty close to being right on.

 

[keny]

That's good to know , I think I may invest in one of those inline voltmeter's, they could come in handy

 

[trents]

The two unlocked cores seemed to draw a total of about 60 more watts under load when overclocked to 3.8. One test with the watt meter that would have been good to do that I haven't done yet is to see what the differential power draw between the CPU as a four core and as six core at stock frequencies and voltages. When you get your watt meter maybe you can run that one. Of course the other unknown here is whether my Zosma's cores were locked for marketing reasons or out of spec reasons and if the latter, how much out of spec.

 

[keny]

If its only drawing 150 watts under load, and overclocked, I can't see it being out of spec at all to be honest, 6 cores stable undrr prime would leave me guessing marketing.

 

[Neuromancer]

the 140W TDP rating on the motherboard, is positive comment not a limitatino.

Many boards come with unsinked fets and can only handle a 90W TDP, once overclocking a thuban or unlocking a quad and blowing past thatthe board gets burned up.

I have not seen a board that says "rated for 300W TDP CPUs" yet because honestly 140W is the highest CPU TDP that is made.

You should be fine pushing 150W through on load, and I expect could break it fairly consistently, just monitor the VRMs for heat under heavy load conditions a few times.

If the sinks get a little warm they are working. If they do not change temp at all... make sure there is contact, or you just aren't pushing the VRMs yet. If they get very warm then tone it down!!

 

[trents]

There is one sink for the SB, one for the NB and another that covers both the fets and the VRMs. The latter two were both were getting pretty warm to the touch but not quite to the painful stage.