PSU limit or graphic card limit

leoncao · 4 Sep 2012 at 17:59

Specs: i5 2500k @ 4.4GHz + ASUS 560Ti 448 + xfx core 550W PSU

I was trying to OC my card to its limit. I believe it is rated at about 200+W load. I increased the voltage to 1.075V from 1.0V and pushed it to 853/210 (core/memory) it passed 3Dmarks 11 with about P6250 scores. When I tried to push it a bit more 863/2100, it would not finish 3Dmarks 11 (it rebooted). If I keep voltage to 1V and set the same clock it would not reboot, rather it caused "driver stopped working" error and returned to desktop screen. I know every card can be different, but I have seen reviews with higher clocks. I suspect the reboot might be caused by insufficient power? On the packaging of the card it says 550W is the minimum. Which do you guys think is the bottleneck?

Bacon? · 4 Sep 2012 at 18:30

It wouldn't be the PSU thats the problem but rather the card isn't stable enough to support the overclock. Nvidia cards cannot overclock anywhere as much as ATI cards.

Rusty0611 · 4 Sep 2012 at 18:41

Bacon? said:
Nvidia cards cannot overclock anywhere as much as ATI cards.

That generalisation simply is not true.

leoncao · 4 Sep 2012 at 20:11

Bacon? said:
It wouldn't be the PSU thats the problem but rather the card isn't stable enough to support the overclock. Nvidia cards cannot overclock anywhere as much as ATI cards.

But I have seen reviews of this card exceeding 900 core.

Bacon? · 4 Sep 2012 at 20:14

Possibly motherboard then?

@Rusty: What Nvidia cards can do large overclocks? The upper market of the 680 can I think but not so much the lower - mid range cards?

leoncao · 4 Sep 2012 at 21:18

Bacon? said:
Possibly motherboard then?

@Rusty: What Nvidia cards can do large overclocks? The upper market of the 680 can I think but not so much the lower - mid range cards?

Motherboard is ASUS P8Z68-V

I thought most power come directly from PSU?

Rusty0611 · 7 Sep 2012 at 00:09

Bacon? said:
Possibly motherboard then?

@Rusty: What Nvidia cards can do large overclocks? The upper market of the 680 can I think but not so much the lower - mid range cards?

660ti, 670 and 680 are all capable of large overclocks. Not as much in percentage terms as their AMD counterparts but this is due to the AMD cards shipping at a very low stock clock speed. I'm not sure that overclocking by 50% is advantageous when the end result is that it performs in line with its nVidia equivalent. My point is that it isn't overclocking above and beyond what the nVidia equivalent is - they both overclock to around the same level of performance. So to call the overclocking headroom a plus point is a little off the mark that's all as it is just a result of low stock speeds.

This is why you often see the AMD cards looking weak in benchmarks but when they're overclocked they often match or trade blows with the corresponding nVidia card (e.g. 7970/680, 7950/670).