Looking to upgrade from a GeForce 8600 GT for online FPS games. Running a
PC Power & Cooling Silencer 470 ATX PSU on a Gigabyte GA-P35-DS3L mobo,
DVD drive, hard drive or two.
Looking for recommendations for the most video card (PCIe) I can run with this.
Not too proud to go Ebay/used.
Thanks!
A very rough rule of thumb, is you can't use more of a video card,
than there are connectors on the power supply.
This is a spec for the Silencer 470. 12V @ 26A. One 2x3 PCI Express connector.
http://www.pcpower.com/downloads/specs_3824.pdf
You didn't state processor, so I'll use some round numbers.
Assume a 95W LGA775 quad. 95W/0.9eff * 1/12V = 8.8 amps.
Two hard drives at 0.6 amps each. One optical at 1.0 amps
when a CD is spinning. Allocation for cooling fans of 0.5 amps.
Total 12V amps so far 8.8+0.6+0.6+1.0+0.5= 11.5 amps
That means, of the 26 amps available, we're left with 14.5 amps.
If we look up a GTX 570, that uses two power connectors,
and a total of 2.6+8+8.8= 19.4 amps. So we're short by about
5 amps, and one PCI Express connector.
http://www.xbitlabs.com/articles/graphics/display/geforce-gtx-570_4.html#sect0
If we drop down to a GTS 450, that uses one connector
for power and a total of 2.7+5.2=7.9 amps. And the article
shows other interesting cards such as GTX 460 we could check out.
http://www.xbitlabs.com/articles/graphics/display/nvidia-geforce-gts-450_4.html#sect0
The GTX 460 1GB card uses two power connectors and the
amps on +12V are 2.3+6+3.4= 11.7 amps. That would be
getting pretty close to the 14.5 amp remaining limit. To make
the second power connector, we could try a four pin
Molex to 2x3 PCI Express connector, to supply the 3.4 amps
input. (I don't like adapters, and running the 6 amp
input off an adapter might be a mistake.)
http://www.xbitlabs.com/articles/graphics/display/nvidia-geforce-gtx-460_6.html#sect0
The GTX 460 768MB isn't that much less. Still two power
connectors and 1.6+2.2+6.2= 10 amps of 14.5 left.
http://www.xbitlabs.com/articles/graphics/display/gigabyte-gv-n460oc-768i_4.html#sect0
So to avoid temptation, you could find a card with one
PCI Express connector, and chances are it will be OK.
Now, to work some total power numbers. We can check current
on 12V, but also need to estimate total power as well.
We'll use the GTS 450 at 7.9 amps. The processor and
drives were 11.5 amps. Total 12V amps is 19.4 amps.
12V * 19.4 amps = 232.8 W. Add in 5W per each hard drive,
7.5W for optical drive logic board, 50W for motherboard
chipset and RAM, 10W for USB loads, brings the total
estimate to 232.8+5+5+7.5+50+10=310.3W. The standard 50W
mobo allocation is probably too much, but the overall figure
is "comfortable" at 310W of 470W available. And the current
of 12V @ 19.4 amps of 26 amps available, leaves some room as well.
If you went with the GTX460 768MB at 10 amps, that's 2.1 amps
more than my worked estimate, so would add 2.1A*12V=25.2W
to the total, or 335.5 watts. Still doable, but would
require using a 1x4 Molex to 2x3 PCI Express adapter
to make a second connector. I'd plug that to the 2.2 amp
input power connector.
Xbitlabs used to be a good source of power numbers, but
they're getting lazy now, and doing "Anandtech style"
reviews. Which is a shame. When no power numbers are
available, I have to take the useless "estimates"
from pages here (estimate probably from Nvidia or ATI).
I much prefer measured values to estimates, as sometimes
the estimates are just too high for planning purposes.
Statistically, I'd need to measure a hundred video cards,
get a mean and standard deviation, to have useful data.
Measuring one card isn't very good (so my statistics professor
would tell me), but I happen to like it
http://www.gpureview.com/videocards.php
Don't forget to check the benchmarks on the card you select.
The video card business is dishonest enough, that sometimes
a 2008 card can be faster than some cheap 2012 card. Nvidia
has rebranded some of their GPU chips, as many as three times,
so just because the "model number is higher", doesn't guarantee
a screamer of a card.
Good luck,
Paul