Quoting: EhvisThe wild card in your system is actually the Xeon CPU. Maybe something strange is going on with that. Maybe something related to power save?

cpu governor is set to "performance", so that shouldn't be a problem...
though: for some time now, even in powersave mode, the cpu is running at least at 3.4GHz (according to xosview), but it should be able to go as low as 1.2GHz (did so some months ago)... so problem might be: kernel (5.12.4) can't set / read it properly anymore or some of the security issue fixes broke that... see output of '/proc/cpuinfo' at bottom, the powermanagement state can't be read

Quoting: XpanderOhh i didn't even notice that its a Xeon CPU... that sounds quite bad for pairing with something like this high end GPU tbh... Maybe its missing some instruction capabilities that the native game makes use of?

it's definitely not a strange pairing; we have stuff like that at work too, core-i<..something..> with a quadro or firepro and xeons with a geforce... and if you're looking at the workstation market it's not unusual to get a xeon-w (not the other xeons for server/multi-cpu environments: E3/E5) with a highend geforce or radeon... so that pairing shouldn't create a problem and doesn't in other games which are quite new and demanding...

the xeon-w 21xx is skylake-w architecture, so it has the same stuff as a normal skylake (6.th gen core-i) plus some goodies for better vector processing and support for ECC-memory and larger caches, blablabla.... see cpu-info at bottom... and as even the recommended cpu on the steam store page says: 4th gen core-i (i7-4770k) the cpu should be good...

unfortunately there's only 50 min left for testing.. otherwise i can't get a refund anymore, and i'd like to do that if i can't get it to run properly 'til wednesday.....

 
/proc/cpuinfo : 
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 85
model name : Intel(R) Xeon(R) W-2145 CPU @ 3.70GHz
stepping : 4
microcode : 0x2006a0a
cpu MHz : 3700.000
cache size : 11264 KB
physical id : 0
siblings : 16
core id : 0
cpu cores : 8
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 22
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon
 pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_dead
line_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single pti intel_ppin ssbd mba ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsg
sbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb intel_pt avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc 
cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts hwp hwp_act_window hwp_epp hwp_pkg_req md_clear flush_l1d
vmx flags : vnmi preemption_timer posted_intr invvpid ept_x_only ept_ad ept_1gb flexpriority apicv tsc_offset vtpr mtf vapic ept vpid unrestricted_guest vapic_reg vid ple shadow_vmcs pml ept
_mode_based_exec tsc_scaling
bugs : cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs taa itlb_multihit
bogomips : 7399.70
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 48 bits virtual
power management:

.... other 15 logical cores with same output ....