First off, wow this forum is dead, last thread 2 years ago?

Well I reinstalled my beloved Grid on my friend's computer, unfortunately I keep experiencing issues: in the race, the game often freaks out - freezes up and just visually repeats 2 last frames or something; but the rest of the game still runs, sound and all.

It usually clears up when I alt+tab away and back into the game. Although, sometimes I need to do it a few times because on return there's another glitch or a black screen.

Fun part is, the issue is track- and situation-dependent. On some tracks it never happens, while on others it happens in almost specific instances. The worst one is Le Mans, where it always freaks out at start, then after 6 hours when it gets darker, and once again when night drops.

Additionally, very often it bugs out just before I crash or hit a barrier.

But after alt-tabbing from these issues (if it works), the rest of the race is clear.

So this tells me this isn't as much of a graphical glitch but rather related to loading - so cpu or memory?

I've tried every trick I found or thought of, including: the -novirtual command line option, limiting affinity to 0 cpu, editing xml files to limit cpu usage to 1/2/4 cores, disabling msaa/bloom/postprocessing, using vsync in game or within the drivers, reinstalling OpenAL, switching sound hardware acceleration on/off, switching fullscreen/windowed, running the game in XP/Vista/7 compatibility mode as admin. Graphics quality settings don't change anything, whether it's on lowest or highest. It's always the same.

The PC is:
AMD Ryzen Threadripper 1920X 12-Core Processor (24 CPUs), ~3.5GHz
Gigabyte X399 AORUS PRO
AMD Radeon VII
32GB 2133 MHz DDR4
some SSD RAID storage... can't figure out what it is, but that doesn't matter I think
Windows 10 Pro 64-bit (10.0, Build 19044)

No problems in device manager or dxdiag

I'm a bit rusty regarding these things and this isn't my computer so I don't know what else I could try. Last time I played this on my old Intel Q6600, GTX660 and Win7, it ran like a charm ;) ...

Sooo... Ideas? Maybe other forums where people may still discuss/play this game? It seems to be forgotten everywhere.

I remember having slowdowns during races as well and afaik it didn't have anything to do with AMD processors.
It had something to do with the replays saving every once a while during a race but when looking into it I hadn't figured out a solution. PCGamingWiki at least doesn't make any mention of it.
Perhaps I read about it on the Steam forum.

True, seems unrelated to AMD; I've scoured the Steam forums last night and it seems a few people have the issue with Intel systems too, the common denominator being Windows 10. How surprising.

I've seen advices regarding the replays, but they were always related to other Codemaster games, so initially I dismissed it. Now I've checked again; and yea, RDGrid also has a replay.pbf file in C:\ProgramData\Codemasters\GRID\DataCache\<username>\replay\

Sadly, no dice for me here either - deleting, or creating a dummy read-only replay.pbf doesn't solve the problem. Not even when disabling fullscreen together with this, that actually just makes things worse (my alt-tab fix stops working).

Funny thing though, doing that replay change, and/or disabling ghost cars in the profile options, seems to have some effect - the Le Mans race bugs out in different times than before. Still in predictable ways, just differently.

So... Ya I dunno.