PNY GeForce 8800GT with Antec Neo 500?

Twist86

Active Member
This is a good link I was given when I ask the same question.

http://www.computerforum.com/90110-power-recommendations-video-card.html

I was using a corsair vx450w with +12V 33A my 8800GT from EVGA and it wasn't enough to power it when 100% maxed out no OC it ran Crysis medium with x8 aa no issues but Stalker caused it to pull more then the psu could supply oh the Irony there am I right?

I dunno how your PSU fairs but this is what my issue was and I don't claim to be a expert so giving you the facts to decide.
 

StrangleHold

Moderator
Staff member
I have this PSU: Antec Neo Power 500 500W ATX12V Power Supply.

Can I run this GPU: PNY XLR8 GeForce 8800GT 512MB PCI-e 2.0?

It says that it requires "a minimum 400W system power supply (with 12V current rating of 26A)."

I'm not sure how to tell on the "12V current rating of 26A."

It should be fine. it has to total 38 amps. on the 12V rail. Why are you getting that card? Look at this one, same spec. just a newer model.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814133232
 
Last edited:

hermeslyre

VIP Member
This is a good link I was given when I ask the same question.

http://www.computerforum.com/90110-power-recommendations-video-card.html

I was using a corsair vx450w with +12V 33A my 8800GT from EVGA and it wasn't enough to power it when 100% maxed out no OC it ran Crysis medium with x8 aa no issues but Stalker caused it to pull more then the psu could supply oh the Irony there am I right?

I dunno how your PSU fairs but this is what my issue was and I don't claim to be a expert so giving you the facts to decide.

That's funny, because I've heard (and would undoubtedly think) that that PSU is enough. The stock 8800gt only pulls 8a from the +12v under max load. 33a should be more than enough, unless you have more load on the +12 than the norm.

Edit: or the PSU might be overly hot, the amount of power a power supply can deliver goes down the hotter it gets. A bad efficiency rating can contribute to heat as the difference in wattage drawn from the wall and wattage supplied gets converted dirrectly into heat. That PSU has an excellent efficiency however..
 
Last edited:

Twist86

Active Member
That's funny, because I've heard (and would undoubtedly think) that that PSU is enough. The stock 8800gt only pulls 8a from the +12v under max load. 33a should be more than enough, unless you have more load on the +12 than the norm.

Edit: or the PSU might be overly hot, the amount of power a power supply can deliver goes down the hotter it gets. A bad efficiency rating can contribute to heat as the difference in wattage drawn from the wall and wattage supplied gets converted dirrectly into heat. That PSU has an excellent efficiency however..

I dunno wtf was the issue all I know is Crysis ran my PC @ 40c on the CPU and GPU @ 60c.
Stalker runs my CPU @ 45c and GPU @ 62c makes me think I should have tried high settings without aa.

Also I doubt it was getting to hot my room is 80F and I had attached a 120mm on the back side to pull more air through it since it only had 1 on the bottom.
Either case I hooked it up to a friends PC running a 2.4ghz Athlon single core and a 7600GT and it works without making scary sounds. The new 750w works like a charm...running 2 8800GT and now Stalker cries vs making my PSU cry.
 

StrangleHold

Moderator
Staff member
That PSU is very good, however just a word of caution, you cannot simply add the 12V rail amperages and say its total is x.

I doesn't work that way.

Of course it doesnt. When did I say it did? It has 38 amps. total on the 12V rail. There are 3 rails with 17amps total pull on any one rail. how does 17x3 add up to 38 like I said, no it would be 51 . You take the total watts on the 12V rails and divide it by 12. It has 456 watts total on the 12V rails= 38 amps.
 

philgons

New Member
Workin' Like a Champ

Popped it in last night, and it's working quite nicely. Thanks for all the suggestions and help.
 

Okedokey

Well-Known Member
Of course it doesnt. When did I say it did? It has 38 amps. total on the 12V rail. There are 3 rails with 17amps total pull on any one rail. how does 17x3 add up to 38 like I said, no it would be 51 . You take the total watts on the 12V rails and divide it by 12. It has 456 watts total on the 12V rails= 38 amps.

It doesn't work like that mate as under ATX standards, 12V+1 is dedicated to the CPU, so any unused current on that rail is effectively trapped. Anyway, you missed the point, these PSU's are not "true" multi rail PSUs. I doesn't matter anyway...
 

StrangleHold

Moderator
Staff member
Never said they were. I said that 38 amps total is the most that is fed to the 12V rail on that P/S. Dont care if it has 1 or 12, a real divided rails, fed off 1 rail into 4 or how its divided up between the rails. 38 amps is the most the 12V rail is getting.
 

Okedokey

Well-Known Member
Again, that's not how it works mate, but you know what, i have explained this at least 20 times on this forum. It may be able to theoretically deliver 38A "the" 12V rail, but unless you have a true multi rail design (or a strong enough single rail) AND because they are limited by safety and ATX design standards, you can only deliver 20A on each rail max. Add to that, the fact that 12V+1 is dedicated to the CPU, and any unused wattage will be trapped, you are PRACTICALLY not actually able to deliver 38A, even if you use ohms law to calculate the max potential current via the method you described.

To clarify, it has 3 x 17A rails right. Using ohms law, you have calculated that it can deliver a total of 38A?

Well, consider the fact that 12V+1 is dedicated to CPU. A CPU uses what, 7A? That means that the other 10A (in this case) is trapped on the 12V+1 rail. So, even if you could add the other two rails, you would find that only 304 watts is available to the remaining system requirements. This means that in reality only 25A is available for the system to power everything other than the cpu.

That was my point.
 
Last edited:

StrangleHold

Moderator
Staff member
Thats true, the 12v CPU rail is just dedicated to itself and no other part of the system can pull off it, but you cant just subtract the CPU 12V rail max amps. The CPU rail doesnt hold 17 amps just for itself, that just the max that can be pulled off it, like the rest of the rails.

I see what your saying, but the CPU rail just doesnt hold a certain amount if amps. Its just the CPU is the only thing pulling off the rail.
 

hermeslyre

VIP Member
Using ohms law, you have calculated that it can deliver a total of 38A?

This isn't very practical in our [forum assistance] environment though. If The OP would give us full specs of the PSU, whether or not it's modular, because Modular PSU's have inherently higher resistance due to all the extra back-end connectors and such, all the devices connected to the PSU, Even how these cables and connectors are put together, because just a little wire management can lower resistance in the wire/connector considerably. This may be alittle of subject, I just wanted to say this.

Thats true, the 12v CPU rail is just dedicated to itself and no other part of the system can pull off it, but you cant just subtract the CPU 12V rail max amps. The CPU rail doesnt hold 17 amps just for itself, that just the max that can be pulled off it, like the rest of the rails.

I see what your saying, but the CPU rail just doesnt hold a certain amount if amps. Its just the CPU is the only thing pulling off the rail.

The CPU rail does generally have unused power, inacessible to other rails. Because most "multiple rail" systems have isolated rails. The Pci-e power connectors are always placed on another OCP relegated rail, and due to this cannot pull power from another rail as is. Most that is, some I hear have "power sharing" capabilities due to a high OCP trip, and advanced power regulating MOSFET's or something like that. I dunno.
 
Top