atomicWAR :
ok i have no idea what i am talking about and neither do any of these folks...
https://forum-en.msi.com/faq/article/printer/power-requirements-for-graphics-cards (they say 700w)
http://www.geforce.com/Active/en_US/en_US/pdf/PSU.pdf (nvidia says 650W is bare min)
point is 650 watts is on the line...your 600watts may work but its certainly under nvidia recommendation. Now i am not saying it won't work. I am saying its not the wisest move for system longevity. If you deny that then i would question your skills to be honest. I know Tom's has long had a low PSU Watt contingent over SLI. Making systems that just barely slides under a PSU capabilities but i say that is unwise and irresponsible to give such advice without a disclaimer as i did. It is better to have a buffer in wattage to account for cap wear (which i see you did do according to your numbers) then to have a fried system that needs replacement. I will always give the safe advice first and when its in the gray area like now..i will give a disclaimer so not to give someone a head ache they don't want or need.
1. No, nVidia very clearly says what is published on their web site:
Thermal and Power Specs:
Maximum GPU Temperature (in C) 99 C
Maximum Graphics Card Power (W) 170 W
Minimum System Power Requirement (W) 500 W
Supplementary Power Connectors Two 6-pin
A system w/ 1 card requires 500 watts .... a 2nd card requires an extra 170...and these are conservative numbers
2. Your link very clearly states that an XFX 650 watt PSU is acceptable.
3. These recommendations you quoted are made with the mindset that not all PSUs are created equal. It is very common for a PSU to be incapable of outputting it's rated power. The XFX in question is **not** one of those PSUs
4. The recommendations you quoted are "system recommendations" and they are based upon the card being paired with the CPUs and other components
of it's time. As shown in the linked tests (Guru3D), the CPUs in use at the time, the one it was actually tested with and the one upon which the 700 watt recommendation was based were quite capable of pulling 277 watts , far more than the 84 watt stock rating (135 overclocked to 4.7) of his actual CPU. One should not go out and buy a bigger PSU based upon the CPU that he does not have but on the one that he does have. How do you not take into account the difference between the 277 watt CPU which served as the basis of the recommendation and as far as we know an 84 watt CPU .... a difference of almost 200 watts ?????
Even if we OC his CPU to 4.8 GHz level power consumption, it is still only 135 watts ....still 142 watts lower than what the OP has.... so if all the recommendations you quote "from the time" are based upon 9xx series 277 watt CPU's, what happens when we subtract that 142 watts from the 750 watt recommendation ? We have a 600 watt power requirement is what we have.
5. I have been building Windows PCs for over 23 years and been managing or participating in PC Hardware based forums just as long
6. I actually **own** the 2 GPUs in question .... I have them overclocked 27% ... I have **physically measured** the power pulled from the wall with a power meter (not guessing) using a PSU
with 6+ year old caps.... it doesn't get near 650 watts .... and the
OP said nothing about his CPU being overclocked 20% and his GPUs being overclocked 27%.
Just because you "read it on the internet" doesn't make it factual.
https://www.youtube.com/watch?v=3DZbSlkFoSU
Even is the source is legit, the recommendation can not be taken as gospel unless the underlying assumptions behind the recommendation are valid. Its been clearly demonstrated that they are not.
A Power Meter measuring the actual load under conditions far worse than the OP stated is certainly factual and more applicable than using a load for a CPU which does not exist in this build.
The fact that the manufacturer of the card says it's OK and will not void your warranty if using the PSU in question, that is factual. And they said that was OK using CPUs far greater in power demand which existed when the card was released.
7. While it is wise to be conservative when **guessing** at a potential max load. I'm not guessing.... I measured it and at far greater load then the OP has indicated his plans include.
8. I used 20% capacitor aging in my calcs whereas that is overly conservative for the PSU in question.
9. The 650 watt may have been "on the edge" back in the day .... but that edge was set by the people who actually make and warrant the card (are we questioning their skill set too ?) knowing full well that:
a) The CPU being used could pull up to 277 watts, we don't have that here:
b) The PSU in question may not have been actually able to deliver its full rated load
c) The PSU in question may have had much cheaper caps than the XFX model and therefore would be subject to much more capacitor aging than
The above was all factored into their recommendation... this is after all what they do for a living
10. All that being said, I would not recommend buying a *new* 650 watter for such a system. No sense saving $5 - 10 when ...
a) PSUs operate at their best efficiency point at 50% load
b) As PSU's bear their max rated load , ripple increases and voltage stability decrease, both of which can be detrimental to overclocking
c) The PSU cooling system is designed to handle the heat load at rated load.... this means your fans will b spinning at the upper range most of the time.
But if you have a 650 watter and are budget limited, sizing a PSU based upon outdated recommendations which are in turn based upon a high wattage CPU that isn't there is nothing other than a waste of money.
Running the system at stock is certainly not a danger. I would want to do actual load tests before doing any overclocking .... it will cost $17 for a suitable meter to do that.
Facebook
Twitter
Instagram