The FSX bottleneck

[dazz 69]

EDIT: mmm, flawed tests... again?

[luckyman 0]

what>? What kind of tests?

[dazz 69]

I'm testing GPU overclock with different settings and at different airports. With little scenery complexity, there seems to be no CPU bottleneck anymore, but the results are confusing so far.Sorry for rushing to post, I'll report back if I find something interesting, but I think there are situations where a fast GPU may help to some extent

[UlfB 7]

I'm testing GPU overclock with different settings and at different airports. With little scenery complexity, there seems to be no CPU bottleneck anymore, but the results are confusing so far.Sorry for rushing to post, I'll report back if I find something interesting, but I think there are situations where a fast GPU may help to some extent

If you have a fast system, such as yours, and move from a 8800GTX to a GTX285 or GTX480 you'll get a significant improvement of performance. A moderate OC won't give you much improvement. I OC:ed my card to 820MHz, but couldn't notice any difference compared to default OC at 756MHz.I'm very interested in what you'll discover!:Peace:

[dazz 69]

Exactly Ulf, it is difficult to make conclusions with the moderate boost on graphics you get OCing the GPU, but at least I think we can tell when the CPU bottleneck has been overcome. If you didn't see any kind of improvement after OCing your 480 that suggests to me you were limited by your CPU in that particular situation.In light scenery environments (almost everywhere if you think of it), I get a hit in frames when I downclock my 460 to 535MHz / 1800MHz memory. That tells me the GPU is limiting my system at that point. There's no difference at stock compared to an 850MHz / 2100MHz overclock, so at stock it looks like the CPU is the limiting factor again. Those results where consistent in both the PMDG JS41 & the MD11I'll benchmark my GPU at those 3 different clocks to have an idea of how much "synthetic" performance the 460 delivers at each clocks and see if it really takes a big GPU downgrade to overcome the CPU bottleneck.Tack

If you have a fast system, such as yours, and move from a 8800GTX to a GTX285 or GTX480 you'll get a significant improvement of performance. A moderate OC won't give you much improvement. I OC:ed my card to 820MHz, but couldn't notice any difference compared to default OC at 756MHz.I'm very interested in what you'll discover!:Peace:

[luckyman 0]

Exactly Ulf, it is difficult to make conclusions with the moderate boost on graphics you get OCing the GPU, but at least I think we can tell when the CPU bottleneck has been overcome. If you didn't see any kind of improvement after OCing your 480 that suggests to me you were limited by your CPU in that particular situation.In light scenery environments (almost everywhere if you think of it), I get a hit in frames when I downclock my 460 to 535MHz / 1800MHz memory. That tells me the GPU is limiting my system at that point. There's no difference at stock compared to an 850MHz / 2100MHz overclock, so at stock it looks like the CPU is the limiting factor again. Those results where consistent in both the PMDG JS41 & the MD11I'll benchmark my GPU at those 3 different clocks to have an idea of how much "synthetic" performance the 460 delivers at each clocks and see if it really takes a big GPU downgrade to overcome the CPU bottleneck.Tack

So good luck with your testesting let us know!

[UlfB 7]

Exactly Ulf, it is difficult to make conclusions with the moderate boost on graphics you get OCing the GPU, but at least I think we can tell when the CPU bottleneck has been overcome. If you didn't see any kind of improvement after OCing your 480 that suggests to me you were limited by your CPU in that particular situation.In light scenery environments (almost everywhere if you think of it), I get a hit in frames when I downclock my 460 to 535MHz / 1800MHz memory. That tells me the GPU is limiting my system at that point. There's no difference at stock compared to an 850MHz / 2100MHz overclock, so at stock it looks like the CPU is the limiting factor again. Those results where consistent in both the PMDG JS41 & the MD11I'll benchmark my GPU at those 3 different clocks to have an idea of how much "synthetic" performance the 460 delivers at each clocks and see if it really takes a big GPU downgrade to overcome the CPU bottleneck.Tack

Varsågod Thanks for your info and keep 'em coming :Applause:

[thunderbolt294 0]

Try dropping the Shader Clock down to the Core Clock speed (Effectively making the card an OC'd ATI 4650, there should be a frame drop after doing that.) And then after test flying with the Shader Clock at Core speeds, bump the Shader speed up 10~50MHz from stock and test again.