Before you jump at anything:
What kind of upgrade would you be planning?
The cpu warning doesn't mean that your CPU load is at 99%+. It means that the main cpu thread took too long for the game to work properly.
So it can mean 2 different things:
1. Your cpu doesn't have enough cores and really is at its limit
2. You have enough cores, but something is taking too much time and AC gives the warning
Your 8100 has 4 cores, no hyperthreading. So 4 cpu threads available and while AC only really needs 2 fast cores for the fps.
ith Windows, Discord and the background AC threads, 4 cores can be loaded completely though.
A 5th core already gives plenty of headroom!
So the 8100 should in theory be fast enough with optimized settings. But might cause issues!
With CPUs that have lower single core performance than the 8100, the fps go down before you run into physics issues but the 8100 will probably give enough fps to race but not have enough cores.
A used 8400 or 8600k should already be enough of an upgrade since they add 2 cores and a bit of clockspeed. And they fit into your motherboard 100% surely!
The k variants are overclockable to gain a lot of performance!
With 8th/9th/10th/11th gen Intels, you can almost always push the little i3 k or i5 k to the same clockspeeds the i7/i9 are hitting. Which is of course rarely mentioned for official benchmarks...
The only real difference is the cache size then, which sometimes makes a difference, but honestly anything above the i5 k is throwing away money if you don't use all the cores for workstation stuff.
This changed with 12th & 13th gen. There, the 12400 and soon the 13400 have by far the best price to performance ratio. They boost a single core almost as high as the k variants (which can't really be overclocked) and have plenty enough cores for simracing!
What motherboard and ram do you have exactly?
If you don't have a Z board, a used non-k will work wonders too.
If you plan a bigger upgrade: the 8xxx,9xxx,10xxx and 11xxx all have almost identical single core performance so the 12400 (ddr4!) or 5600 non-x would be the budget choice currently with the 12400 mobo being able to receive a 13600k in the future and the 5600 mobo receiving a 5800x3D.
Or if you want something really future proof, you can splash out like I did during black Friday and buy a 7600x + B650 + ddr5.
Prices are almost identical to the lowest ones during BF.
Colin's car showed similar behavior a while back and in his case it was a cpu choke. Phy_late ran up a few thousands per lap sometimes!
And like I wrote about Ernie's glitching, AC sadly doesn't check if the positional updates from the clients make any sense and simply pushes whatever each local client sends to the server to everyone else.
If you don't know, Phy_late means that the physics calculation took longer than the tickrate or some percentage of the overall frame time. Which can cause all kinds of weird stuff.
Up to 100 per lap is usually fine, simply causing some mikro-glitching while staying on the expected path but 1000+ per lap can cause a lot of trouble
