Update: The cpu works without a problem. Today I completed benchmarking and didn't occur any issue. Performance has increased significanlty as shown in the results:
Windows 98se Benchmarks: Coppermine 1000EB Tualatin 1.4GHz
3D Mark 99 Max (default resolution)........... 7018...................... 10004
3D Mark 2000 (default resolution)............... 6671...................... 7768
GLQuake timedemo (1280x1024x32).......... 108,3..................... 109,2
Quake II timedemo (1024x768).................. 179,4..................... 265,4
Quake 3 timedemo (1024x768x32).............. 98,3..................... 110,6
Unreal castle fly timedemo (1024x768x32)..... 70,3..................... 78,2
MDK2 (1024x768x32) ................................ 101,7..................... 99,8 (the only strange result; I assume it's because of the gpu bottleneck)
Expendable timedemo (1280x1024x32)............ 62,1..................... 69,6
MS-DOS 7.1 Benchmarks:
3D Bench 1.0c ............................... 658,4 ...................... 1000+ (maxed it only dials 0.00)
Chris's 3D Benchmark ..................... 454,2 ..................... 858,5
Chris's 3D Benchmark (640x480)........ 149,1 ..................... 300,5
PC Player Benchmark........................ 235,5 ..................... 374,9
PC Player Benchmark (640x480)........ 181,8 ..................... 233,3
Doom timedemo (max details)........... 121,4 ..................... 126,4
Quake timedemo(640x480)................ 56,5 ..................... 63,9
I'll continue benchmariking with an FX5900XT.
PC1😜 III-S 1.4GHz, GA-6VTXE, 512MB SDRAM, Albatron FX5900XTV 128MB, SB Live! 5.1
PC2😜 III 800MHz, MS-6178, 256MB SDRAM, 3DFX Voodoo3 2000 PCI, Creative CT4810
PC3😜 MMX 200MHz, SY-5EAS5, 128MB SDRAM, Diamond Monster 3D, Diamond Viper V330, ESS 1868F