enough power for a 4870?

jedimaster1138 · Post by **jedimaster1138** » Tue Jul 08, 2008 11:13 am

So when I built my machine last fall, I carried over a 7600GT from an old system, knowing that in the near future I'd get a modern dx10 card. That time is now, CoD4 is a bit pokey with that 7600GT and hl2 could use a couple more FPS. With Diablo 3 and Starcraft 2 coming, I'm even more motivated. It looks like the 4850 and 4870 are lovely cards for the price.

My question is...do I have the amps to run a 4870 ? (or even a GTX 260 if it indeed drops in price...)

Current system:

Antec P182 with installed Antec Tri-Cools x3
Corsair CMPSU-620HX
Gigabye GA-P35-DS4 Rev 2.0
Intel Core 2 Quad Q6600 + Arctic Silver 5 + Thermalright Ultra-120 Extreme + Scythe SFF21E (1200 RPM)
4x 1 GB Crucial Ballisitx DDR-800 4-4-4-12
2x Western Digital WD2500YS â€“ 250 GB - for system drive RAID 1 set
2x Western Digital WD5000YS â€“ 500 GB - for data drive RAID 1 set
Samsung SH-S203B 20x DVD+-R/RW etc
EVGA 7600GT + Arctic Silver 5 + Zalman VF900 Cu + FanMate2 (imported from old system)
Dell 2407 FPW (1920x1200) LCD (also imported from old system)
Additional Scythe SFF21E mounted at front panel, upper hard drive bay, via Molex
SoundBlaster X-Fi Fatality XtremeGamer
Windows Vista Ultimate 32-Bit

My quick back of the envelope math is that I'm ok, power wise, but I want to check with the wise and learned folks at SPCR.

I have evey intention of ripping off the stock cooler from the 4870 and installing something much more quiet and efficient ( I like Thermalright a lot, but would run with an Accelero if it's proven to be better)

I'd have to move the 2 drives I have in the upper bay of the p182 to accomodate the length of the 4870 (although probably not the 4850) but that's not a big deal.

Thanks in advance.

krille · Post by **krille** » Tue Jul 08, 2008 11:34 am

If you'd asked "what Corsair PSU would you recommend me for this system", people would probably have suggested the VX450W around here. Unless you're going Cross-Fire and/or overclocking that should be more than enough.

Power Supply Fundamentals: REAL SYSTEM POWER REQUIREMENTS if you're interesting. To be safe, add 10W per HDD. Even at stock the D950 CPU draws substantially more than your Q6600.

That 620W PSU is overkill for your intended system.

We don't really now about the latest TR yet, so the AC Accelero S1 is still the king of GPU cooling.

soloman02 · Post by **soloman02** » Tue Jul 08, 2008 3:47 pm

I have a related question. Would my 500 Watt Seasonic PSU w/ 34 amps on the 12 rail (combined, I did the math) be enough for the 4870 X2?

If not, how is the quality on those Video card 5.25 inch drive bay PSU's?

Also, my board (P35 chipset) is not PCI express 2.0, would that limit the 4870X2's performance?

krille · Post by **krille** » Wed Jul 09, 2008 6:12 am

soloman02, the 4870 X2 is an unreleased card. 408W is plenty of wattage however and should be more than enough. / Afaik using multiple PSU:s within one system should be avoided regardless of their individual qualities, besides I doubt they're that great anyway. Your 500W Seasonic should be plenty either way. / Again the 4870 X2 is an unreleased card, but there probably won't be any noticeable difference.

soloman02 · Post by **soloman02** » Wed Jul 09, 2008 2:39 pm

I know it is unreleased, but I assume the power requirements will be very similar to two 4870's in crossfire. the only other potential problem is if the PCI express slot I have (version 1.1 I think) will restrict the performance of the X2.

thejamppa · Post by **thejamppa** » Wed Jul 09, 2008 3:15 pm

soloman02 wrote:I know it is unreleased, but I assume the power requirements will be very similar to two 4870's in crossfire. the only other potential problem is if the PCI express slot I have (version 1.1 I think) will restrict the performance of the X2.

The bandwith restriction between 1.1 vs. 2.0 is something you really don't need to be worried. Most games will make CPU bottlenecking before the PCI-E bandwith.

soloman02 · Post by **soloman02** » Wed Jul 09, 2008 6:23 pm

I saw some power requirements for 4870's in X-fire and it didn't look pretty. Granted it was total system power with a quad core, and wasn't DC power but AC... it was still high at about 450 Watts AC. I believe that is less in DC watts, but not by a whole lot. I only have a 500 W PSU which is 80% efficient at worst (its an 80 plus supply). That leads me to suspect that my current PSU will not be enough to handle the power monster of the X2.

Post by **NeilBlanchard** » Wed Jul 09, 2008 6:33 pm

Hello,

The efficiency calculation goes the "other" way -- if is is drawing 450watts from the wall, then it is using ~80% of that to run the machine; or 360watts. This leaves (at least) 140watts of headroom -- the rating on a power supply is for the DC output; not the AC input.

What dual core do you have? Oh -- the E2200. Is that a 0.45 family? You machine uses less than 200watts, I'd guess...so with the new card, it might peak above 250watts?

For comparison, my Athlon 64 X2 4200+ (0.90) with 4GB of RAM, 3 hard drives and a 6600GT uses just 122watts at full CPU load. Before, I had 2GB and dual 7600GS cards, and it drew 184watts while gaming and Folding at the same time. Your CPU is much lower power use than my 3+ year old X2.

soloman02 · Post by **soloman02** » Wed Jul 09, 2008 8:35 pm

The E2200 is a 65nm part with a TDP of 65W. Thanks for clearing up the efficiency part, I couldn't remember which way it went.

drjunk · Post by **drjunk** » Thu Jul 10, 2008 12:50 pm

krille wrote:soloman02, the 4870 X2 is an unreleased card. 408W is plenty of wattage however and should be more than enough. / Afaik using multiple PSU:s within one system should be avoided regardless of their individual qualities, besides I doubt they're that great anyway. Your 500W Seasonic should be plenty either way. / Again the 4870 X2 is an unreleased card, but there probably won't be any noticeable difference.

I know members here...me included (id like to think)...have a sensible view on psu requirements..."1000w+ psu" is a swear word

. But i would have suggested a higher watt psu...maybe a 600-800w. In most cases psu's are most efficient at 50% load.

I just think 500w is cutting to close to the bone.

jaganath · Post by **jaganath** » Thu Jul 10, 2008 12:58 pm

drjunk wrote:I know members here...me included (id like to think)...have a sensible view on psu requirements..."1000w+ psu" is a swear word . But i would have suggested a higher watt psu...maybe a 600-800w. In most cases psu's are most efficient at 50% load.

I just think 500w is cutting to close to the bone.

it's not really a problem; if he connects up the card and his system won't power up, then you know the PSU is insufficient (if all other issues have been excluded). nobody wants to chuck away a perfectly good 500W PSU for no reason. also, FYI, altho the E2200 is rated at 65W, if it's like the rest of the E2XX0 family, the actual usage will be in the 30-40W region.

soloman02 · Post by **soloman02** » Thu Jul 10, 2008 5:44 pm

I know members here...me included (id like to think)...have a sensible view on psu requirements..."1000w+ psu" is a swear word . But i would have suggested a higher watt psu...maybe a 600-800w. In most cases psu's are most efficient at 50% load.

I just think 500w is cutting to close to the bone.

Since the PSU is 80 Plus certified, the minimum efficiency is 80% at ANY load.

I am still worried about not having enough power since I like to overclock both my cpu and gpu, but If I need to buy a new PSU when I get a 4870X2 I will do so. I would rather not buy one now since I won't see any gain right now. Besides, maybe those 620 watters will be cheaper come September anyway

.

As long as the OP and anyone else who wants a 4870 / X2 have a PSU that is 80 plus certified, they should have enough power provided they select one with enough amps on the 12V rail.

My 8800GT even ran on my old 420 Watt TT with 18 amps on the 12V rail. And that thing had even a worse efficiency of 65%.

darkb · Post by **darkb** » Thu Jul 10, 2008 6:42 pm

I'm not so sure you could run a 4870X2 comfortably on a 500W powersupply.. my mate is running a E6850 @ 3.6ghz and a new GTX 280 on one of the Seasonic S12 600W power supplies, and while it's stable even with the card overclocked, it makes a very loud and disturbing elecrical noise whenever he games with it.. loud enough to hear clearly over his fans

(and yes, it is actually coming from the psu, not the card)

I think the main problem is that both the cpu and video card get all their power from the 12v rails.. and this seems to be near the limits for his psu.

A 4870X2 would use even more power, and might not run.