This is a bit of a mea culpa from me.
In 2022 I started the build of my dream PC. i9 13900k, 2 TB M.2 drive, 32 GB of 5200 DDR5 ram.
…and a 6600XT.
Now at the time it was all I could afford. I just wanted something that would run most games decently. nothing earth shattering but could do the heavy lifting i needed it to. I planned to upgrade later down the road.
For most games it was (and still is) perfectly fine. It ran most of my 100+ game library with no complaints from me.
But there was one game. Arma 3.
Now anyone who knows Arma 3 will readily admit it is a horribly optimized mess. This games drinks ram and chews up GPU’s like they’re candy.
And my 6600XT was crushed underneath it’s massive weight.
Now the problem for me is at the time I was fanatical about the game. It was pretty much the only game I played constantly. I still play it to this day, just not as much.
I would get stutters, massive frame drops and tons of crashes all centered around not enough GPU ram. (the 6600Xt only has 8) I HATED this card and would loudly complain on every forum every time someone would mention it. I sneered at AMD and desperately wanted to go Nvidia.
problem was i still couldn’t afford to upgrade.
But I finally had it last month and so I saved up and bought…
An Intel ARC A770.
But it worked. frame rates went up, crashes pretty much disappeared and and all was good in the world.
At this point I know you (probably) are screaming "Well what the fuck does this has to do with BIOS!?
well let me explain. You see I also wanted a much better m.2 drive so I bought a WD Black SN850X.
but while I was installing the NVME drive I noticed that my PCIe slot was set to gen3 X8. Not gen4 X16.
This solved everything. I went back to my 6600XT as I was having driver issues with the ARC card. and now when I play Arma 3 it runs much smoother. It still crashes because honestly the game needs a minimum of 16 GB of memory on a video card to run (sort of) fairly smoothly, but frames went up, stutters pretty much disappeared and the 1% lows were much more less noticeable.
All because I missed a BIOS setting.
So WHY? why is BIOS still so troublesome? why can’t it detect cards and automatically set the proper settings by itself?
WHY!?
Anyways, that’s all I have to say about that.
BIOS is designed to be super low level and work the best in all situations, regardless of what that is. That means the defaults are usually designed for best overall performance rather than having all PCI lanes allocated to a single slot. Different mobos have different defaults and priorities.
Your mobo default probably makes sure that your 8 and 4x slots or nvme actually have full lanes available, where if you allocate the full lanes for the primary slot you may only have the 8x/4x slots running in 2x/1x mode.
It’s up to you to determine if the 16x slot should have dedicated lanes. I don’t remember ever having to change this on any of my machines, but I mostly run gaming mobos which probably prioritize having a dedicated GPU with full access to PCI lanes.