CPU Upgrade

[Kobblepot]

Hello,

I received a second GTX 780 as a gift to add to my PC for SLI. The problem is that my CPU (i7 2700k) doesn't utilize the SLI as well as I have seen the GTX 780 SLI perform. This is mainly do to the fact, at least to my understanding, the PCI-E revision 2.0 and the PCI-E lanes of 16 are holding the performance back. My budget is around $600, and I don't mind raising it if there is a reasonable reason to. I also was looking into upgrading my current motherboard (ASUS Z77 Sabertooth) if needed. 

 

Thanks in advance.

[Dzzope]

All you need is PCI-E 3.0.. get whatever will allow you to do that, you seem capible of finding specs and understanding them.. check if you can get a motherboard that will allow you it with your CPU, or if your motherboard does, get a cpu which will allow it to work.. (IIRC, you'll just need to bump to a 3xxx chip)

 

 

Or sell the 2 780's and get a single 970 / 980.

[Godlygamer23]

PCIe 2.0 x8 is fine for 780s. The highest number of lanes you can get in a PCIe is 16. Can you be more specific in the performance you're getting with your 780 SLI set up versus other 780 SLI setups?

[lopj245]

http://pcpartpicker.com/p/b4hVgsor you can get an i7 instead of the i5.

[Dzzope]

PCIe 2.0 x8 is fine for 780s. The highest number of lanes you can get in a PCIe is 16. Can you be more specific in the performance you're getting with your 780 SLI set up versus other 780 SLI setups?

hmm, no.. it'll be throttling it some.. a 690 was throttled on PCI-E 3.0 x8 vs x16 by about 2 - 5%.. so going down to 3.0x4 (Same effective speed as 2.0 x8) will have an impact... 

 

3.0 x8 is fine though. Minimal impact if any.

[Godlygamer23]

hmm, no.. it'll be throttling it some.. a 690 was throttled on PCI-E 3.0 x8 vs x16 by about 2 - 5%.. so going down to 3.0x4 (Same effective speed as 2.0 x8) will have an impact... 

 

3.0 x8 is fine though. Minimal impact if any.

2-5% isn't much at all. I didn't say it was perfect and that there was no performance reduction. What I said was that PCIe 2.0 x8 is fine for 780s and it is. 2-5% performance lost isn't much and is nothing to complain about.

[Dzzope]

2-5% isn't much at all. I didn't say it was perfect and that there was no performance reduction. What I said was that PCIe 2.0 x8 is fine for 780s and it is. 2-5% performance lost isn't much and is nothing to complain about.

 

You missed what I was saying totally.. a 690, was slower by about 5 - 7% on (equivelant of) PCI-E 3.0 16 vs x8.. He's running on essentially x4 in effect half the bandwith at which the 690 showed it was being limited... so it will be having a more significant impact here.

 

grab a second-hand 3770k and be done I say.

[Kobblepot]

I've been getting around 45-50 FPS for GTAV when driving around town at direct x11 with anti-aliasing,v-sync, tessellation, and ambient occlusion off. Also, lag drops in Crysis 3 down to a consistent 45fps with v-sync and anti-aliasing off and shaders down to high. I've seen other benchmarks that boast those games to over 65-70+ at 1080p. I don't know if I'm naive or ignorant about in assuming my system should run about the same, but at any rate the main difference I've seen from their set up and mine is the mobo and cpu. Hence, why I was looking at those two in particular. 

 

I'm also looking for some future proof if possible.

[Godlygamer23]

You missed what I was saying totally.. a 690, was slower by about 5 - 7% on (equivelant of) PCI-E 3.0 16 vs x8.. He's running on essentially x4 in effect half the bandwith at which the 690 showed it was being limited... so it will be having a more significant impact here.

 

grab a second-hand 3770k and be done I say.

This is Tom's Hardware's review of differing PCIe generations with the 690. It lost about 2FPS. Also, you changed your percentage values. You said 2-5% and then changed it to 5-7%. http://www.tomshardware.com/reviews/graphics-performance-myths-debunked,3739-3.html

 

PCIe 3.0 x8 with a 690 is essentially 8GB/s per GPU which then would be equivalent to two 680s running on two separate slots running at PCIe 2.0 x8 each.

[Faceman]

@Kobblepot

Is your 2700k overclocked?  If not, overclock it as high as possible.  There is no reason whatsoever for you to need to switch processors.  The 2700k is still incredibly strong, just dial up the OC.

[Dzzope]

This is Tom's Hardware's review of differing PCIe generations with the 690. It lost about 2FPS. Also, you changed your percentage values. You said 2-5% and then changed it to 5-7%. http://www.tomshardware.com/reviews/graphics-performance-myths-debunked,3739-3.html

 

PCIe 3.0 x8 with a 690 is essentially 8GB/s per GPU which then would be equivalent to two 680s running on two separate slots running at PCIe 2.0 x8 each.

Oops, so I did.. If you look at the other benchmarks he has though from 2011 where they test dual card setups, they have up to a 20% performance drop off on 570's / 6970's.. Considering the higher the frame rate your pushing the more data needs to go to the cpu.. dual 780's in anything that is not REALLY heavy on resources will be cpu bound at x4 speeds.

 

It also varies allot depending on the game how much performance is impacted

http://www.tomshardware.com/reviews/pci-express-scaling-p67-chipset-gaming-performance,2887-9.html