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Is my PSU powerful enough for my system

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abarth_1200

Member
Joined
Jun 3, 2009
Location
Scotland, Inverness
Hi everyone, had my system up and running for a few months now, recently upgraded from a 9800gt to a GTX260 and a Velociraptor hard drive, full specs in my signature along 5 case fans 2 with LEDs, some LED lights and my cpu is overclocked by 33%.

Im concerned about the fact that it is only a 425 watt PSU which seems quite low compared to lot of other peoples rigs but up until now it has been fine, runs cool and quiet perfect,

Here it is http://www.enermaxusa.com/catalog/product_info.php?products_id=150

Should I worry??
 
OP
abarth_1200

abarth_1200

Member
Joined
Jun 3, 2009
Location
Scotland, Inverness
see the thing that puzzles me is the fact that I have ran continuos stress tests on everything for hours and my psu is the coldest part of my rig
 

CompuTamer

Member with Some Fancy Text Under His Name
Joined
Jan 4, 2009
Location
Brandon Mississippi
Eh, i'm not a fan of Enermax personally... i would get a Corsair just to be safe. Check your voltages and see what kind of vDroop you're getting... if the 12volt rail drops a lot under load, then you need a better quality PSU. If not, then i'd say leave it.
 

tinymouse2

Member
Joined
Jun 11, 2009
Location
Surrey, England
GTX 260 peak usage = 270W
E5200 usage is probably around 100W peak
RAM probably about 100W peak
HDD about 10W (HDDs never really use much more than 10W)

So crunching them I get about 500W. This is excluding fans, mobo consumption, any sound/TV cards, optical drives and any periphs plugged in at any one time.

Basically you need more power. I would go with an 850W power suply. Overkill? Yes but the PSU is the one thing you don't want to skimp on.

My 850W antec tru power cost me about £140 (England here) when I brought it. Never whined or given me any problems at all.

So yes, you need more power.
 

cyberfish

Member
Joined
May 23, 2008
Location
London, England
RAM probably about 100W peak
More like 2W.

GTX 260 peak usage = 270W
According to Nvidia it's 182W.
http://www.nvidia.com/object/product_geforce_gtx_260_us.html

E5200 usage is probably around 100W peak
E5200 has a TDP of 65W, so real world power consumption probably less.

So no, 425W is enough. People use big power supplies because they make them. Everything can be calculated or at least estimated with a higher bound.

No need to dump extra money in for nothing.

If you are buying a new computer, it may make sense to get a slightly bigger one, like 500W. But throwing a 425W into garbage and buying a bigger one for future upgrades?... why not save it till when you need it.

If you are really curious, you can get a clamp multimeter or Kill-A-Watt and measure your system's power consumption yourself.
http://www.overclockers.com/forums/showthread.php?t=628688

My heavily overclocked E6300 (65nm, higher power) and 9600 GT takes 222W at FULL load on both CPU and GPU. I'm guessing yours will take 300W at most.
 
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vgta88

Member
Joined
Nov 15, 2007
the e5200 is overlclocked, the current draw of an overclocked processor will not be the same as stock, therefore the tdp will change. but even with more current draw from the cpu it still looks fine after you add everything up. just check voltages on the 12v preferably with a multi meter.

btw i don't think ram only takes 2 watts. might be 2 volts not watts.

i would accept that 100 watt figure for the cpu
182 for the video card
10 for the hdd
10 for hdd
total 302
the rest is all ram baby. (+motherboard)

http://www.enermaxusa.com/catalog/product_info.php?products_id=150

says you got 33 amps combined. = 396 watts

it doesn't seem like this is a bad psu from what i can tell (good ones will handle 110% wattage)

keep in mind these are peak 100% usage values, so there might not be a way to stress both cpu and gpu as well as 2 harddrives and all of your ram at the same time.

=============Estimate/Guesstimate=============

this is going to be interesting on tomshardware they are doing a 4gb memory power consumption review
http://www.tomshardware.com/reviews/4gb-memory-overclocking,2024-11.html
it would be interesting to isolate the memory usage in that system.

i'd guesstimate that the system idle 100 watts consist of 65 watt tdp e8500 stock (highest voltage =1.3625v lowest= 0.85v (from newegg) which results in 65/ 1.3625 x 0.85 =40 watt cpu idle.

the video card at idle I'd just have to guess that it's 28watts (4850)

the remaining 27 watts could be from motherboard.

and I'd give the harddrive an idle power draw of 5 watts.

total this is 100. the rest i'd leave for ram. which makes it look totally reasonable that its doing 50 watts. give or take for 4 gbs.

also check this out some guy just plugged his mobo in psu bare and got a 33watt at the wall. (x 80% for efficiency and you get 26.4 watts) reading
what he wrote is similar to my guesstimates.
http://www.xtremesystems.org/forums/showthread.php?t=227424 post 5 and 7 are a bit all over the place but suggests that overclocking even 33% doesn't make the cpu draw an equivalent amount of power.

===============Conclusion==================
based on the available data and guestimates, the missing values should be 27 watts idle and add 50(load) watts for memory. it doesn't mix very well since I have no clue how much more power a motherboard would use at load (it shouldn't be any different since the 50 watts has motherboard load factored in). Just together you are guaranteed 77 watts min. it should be noted that your cpu probably does not come close to 100 watts even overclocked.

you should be within spec. but kind of running your psu @ 90%+ so it has to be a good model to last like that.
 
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cyberfish

Member
Joined
May 23, 2008
Location
London, England
Power consumption of memory modules is hard to measure, so let's go for the datasheet.

http://www.micron.com/products/dram/ddr2/partlist.aspx

Let's take the Micron production 128MBx16 (2GB) as an example.
http://download.micron.com/pdf/datasheets/dram/ddr2/2gbddr2.pdf
Page 26-27 - DDR2 IDD Specifications and Conditions (Table 10)

The highest current I see is 445mA for x16, "Operating bank interleave read current". No idea what that means, but it's the peak current the stick can draw.

It's rated for 1.8V +- 0.1V, so let's assume you run it at 1.9V.

1.9V * 0.445A = 0.846W.
 

vgta88

Member
Joined
Nov 15, 2007
thats not right. it should be .445a for each 128mb chip. theres 16 in a 2 gb stick as you just posted.

therefore 1.9v x 0.445a x16=13.5 w

this is reading spec so who knows what writing would be or the external memory clock and other parts of the whole memory chip.

( i don't have pdf installed on this computer can't look.)
 

Xtreme Barton

Member
Joined
Jan 17, 2004
can you afford one ? if so get a bigger one. they have some nice silver certified PSU's .. your pc is running close to its use under peaks .. you cant forget its efficiency though either .. 99 bucks or less you can pick up something better .. plus if you sell your current one you can get some of your money back .. not a bad choice .. last thing id want is a PSU having its way with my hardware :D
 

cyberfish

Member
Joined
May 23, 2008
Location
London, England
It offers 3 configurations - 4x512, 8x256, 16x128.

If what you said is true, the higher density chips would take less power!

If each little chip will dissipate 0.85W, they will definitely need heatsinks.
 

vgta88

Member
Joined
Nov 15, 2007
he has an 80 + psu it probably won't matter at the peak 85 % most psu's get

what i'd really like to know, which I made a possibly wrong assumption on is, what voltage rail provides power for memory.
 
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cyberfish

Member
Joined
May 23, 2008
Location
London, England
If we assume his computer draws 200W on average, 5% of that is 10W. At an electricity price of 6c/kWh, 1 hour will cost him $0.0006. To save the $99 for the new power supply, he will need to run his computer for 165000 hours (about 19 years, 24/7).

what i'd really like to know, which I made a possibly wrong assumption on is, what voltage rail provides power for memory.
It probably has a switching DC-DC regulator like the CPU VRM, so it could be supplied by pretty much any rail. In any case, the current is fairly insignificant.
 

cyberfish

Member
Joined
May 23, 2008
Location
London, England
If memory can draw 50W, those tiny heatspreaders (which doesn't increase the surface area like heatsinks do) won't even be close to enough. Memory chips will be melting.

They will need heatsinks comparable in size and surface area to the CPU's.
 
OP
abarth_1200

abarth_1200

Member
Joined
Jun 3, 2009
Location
Scotland, Inverness
Right well thanks for all the replies, I also think I have stirred some discussion up here also.

I plugged my computer into 1 of those kill a watt meters a while ago and it was only drawing like 200 or so watts at full pelt, give me a few minutes and Ill plug it back in and play COD MW2 for a bit to see what max wattage i get

I also did a PSU wattage check like what atomic ferret linked to and it came in a lot lower than 425 watts (including the OC E5200), Apparently I could even run a OC'ed quad core and a few more hard drives.

The only reason I have this PSU is because it cost me £20, I changed from a 600 watt psu with only 19 amps on the 12v rail