I need GPU advice for AMS2

I currently have a 4070 but I'm looking to upgrade because I only race in VR (pimax 5k) and I'm struggling a little with frame rates.
I'm debating between a 4070 ti and an RX 7900 XT. The RX 7900 XT seems to benefit if you have an AMD cpu (I don't, I have an intel i5 8400) so I can't make use of smart access memory, so which of these two cards performs better with AMS2?
Here are my PC specs i5 8400 32 GB dd4 ram, thanks.

 

I've not used AMD before but heard many reports they aren't so great in VR.

I had a 3080 so similar to the 4070 and it was just okay for mixed settings and resolution on my Reverb G2, anything faster than that is going to be a bonus.

For me the 3080 wasn't fast enough so got the 4090.

Have you thought about a CPU/ platform upgrade, that 8400 won't be helping your VR performance. Are you certain the 4070 is your problem?

 

... and here I am plodding along with an RTX2070 Super and a Quest 2....

 

Good ol GTX 1650 and an ancient Dell Xeon Cad unit does the job. No need for VR luckily. But the CPU bottleneck does affect me in ACC, RF2 and MSFS. AMS2 runs pretty good for now.

 

CPU is definitely hurting your performance. A platform upgrade also brings faster express-lanes for gpu and cpu.

 

Yeah, I now the cpu ain't the best but it's a major hassle to replace it. The fastest cpu my motherboard supports is only 9% faster than my current cpu, so we're talking new mobo as well.
Also I've just bought a CSL DD wheel and that seems to hit performance as well. The game ran better with my crappy logitech belt wheel.

 

Doing the mobo seems scary but it isn't really too bad. Especially with the performance you will gain its a big incentive to do it imo.
It's weird the CSL DD hit the performance!

 

I used MSI afterburner/riva to see where the bottleneck could be and I'm a little confused by the result.
The GPU was at 63% usage and the cpu was at 71% overall (between 64% and 86% for the various cores) yet the fps wasn't at the full 90 fps (the maximum for my VR) so I don't get wy the fps wasn't higher given that neither the GPU or CPU were maxed out.

 

This helped me understand CPU bottlenecks, cause that's what you have seeing your GPU isn't hitting 98-100%. You still have 37% more GPU headroom while your CPU isn't keeping up.

When it comes to overall CPU usage, you have to take into account the number of cores/threads you have available. On your quad core, even if one of the cores is fully utilized and bottlenecking your performance, you will only hit around 25% CPU usage, because that core/thread can't get more - it's using all of its share of the CPU. With more cores/threads, this number gets even lower - on my 12 thread CPU, it's only 8.3% (for hopefully obvious reasons). The only way to see 100% CPU utilization is for all four threads/cores (in your current case) to be fully utilized. Which doesn't happen often - it might for you, because you only have 4 cores/threads available on your CPU, but as you get more, it's more and more rare to ever see that happen, because an app has to be able to use so many cores, and most common apps and games don't.
CPU Bottleneck and Hyper Threading post #16

 

I'm thinking of upgrading from my i5 8400 cpu to an i9-9900KF (the fastest cpu that is compatible with my mobo) it is 11% faster than the i5 8400. Is this enough of an upgrade?

 

I would think so

 

Are you using User benchmark to tell you the 11% number?
Id say you will gain quite a lot more than 11%. Like 20% on the single core and 60% on multi threaded applications.
For sim racing you need the fastest single cores, the 9900k should get close to 5GHz while the 8400 is around 4Ghz and also RAM plays a big part so try for some 4000c15 ish dual channel.

 

Yes I'm using User Benchmark, plus I've also watched a few Youtube vids that show framerate differences between the two CPUs. It's encouraging to hear that I will get more than an 11% improvement so I think I'll buy the i9-9900KF or i9-9900K,
2 quick questions - is there any benefit to getting a CPU that either does or doesn't have onboard graphics?
Also will my stock cpu fan be good enough?
Thanks for some great advice, it's really helped.

PS I haven't thought much about the RAM yet, I'll upgrade the CPU then see where I'm at.

 

To test how the CPU compared you really need to be in CPU limited situations so just make sure the videos your watching are proper CPU tests.

I prefer to get a CPU with intergrated just for troubleshooting times but really in our systems it isnt really needed.

No I don't think a stock Cooler will cope.

 

Thanks, one last question, according to my motherboard website it looks like I'll have to change/flash my bios. I have already downloaded the correct bios, should I flash the bios before or after I install the new cpu?

 

It depends on the mobo, on my older z170 I had to update before installing the new CPU, (6600k to 7700k) but on my current z690 I could do it on the new CPU.

 

That one is easy, AMS2 only uses 4 cores out of your 6 cores. But those 4 core are hit SUPER hard due to all the physics calculations. That's 66% of your CPU usage, add other apps and OS running in the back ground and you're probably at 71% CPU usage.

Personally I would recommend not bothering with the 4070Ti or 7900xt, you should probably target the 4080 or 7900xtx and a CPU upgrade in the future.

 

There is definitely some good reading on the forum and it certainly shows 6 threads will not be enough for the game in its current form for VR. Even from my experience going from 6c12t 10600k to my 13600k improved my VR experience considerably.
CPU BottleNeck in Automobilista 2, i3-9100F
Automobilista 2 June 2022 Development Update

 

Rather than start another thread I thought I’d ask here. I’m looking at a 4070ti and a i513600kf setup for my next PC.
Are these a good pairing as I have a 3440 x 1440p display

 

what refresh rate are you aiming for?