According to this you should be able to get into bios with 10900X even with earlier versions. EVGA X299 Dark (151-SX-E299-KR)
CPU Compatibility
Part Number Core Count Frequency PCI-E Lanes BIOS
Cascade Lake-X
Core™ i9 10980XE 18 Cores + HT 3.00 GHz 48 1.19**
Core™ i9 10940X 14 Cores + HT 3.30 GHz 48 1.19**
Core™ i9 10920X 12 Cores + HT 3.50 GHz 48 1.19**
Core™ i9 10900X 10 Cores + HT 3.70 GHz 48 1.19**
Kaby Lake-X
Core™ i7 7740X 4 Cores + HT 4.30 GHz 16 1.00
Core™ i5 7640X 4 Cores 4.00 GHz 16 1.00
SkyLake-X
Core™ i9 9980XE 18 Cores + HT 3.00 GHz 44 1.12*
Core™ i9 9960X 16 Cores + HT 3.10 GHz 44 1.12*
Core™ i9 9940X 14 Cores + HT 3.30 GHz 44 1.12*
Core™ i9 9920X 12 Cores + HT 3.50 GHz 44 1.12*
Core™ i9 9900X 10 Cores + HT 3.50 GHz 44 1.12*
Core™ i9 9820X 10 Cores + HT 3.30 GHz 44 1.12*
Core™ i7 9800X 8 Cores + HT 3.80 GHz 44 1.12*
Core™ i9 7980X 18 Cores + HT 2.60 GHz 44 1.00
Core™ i9 7960X 16 Cores + HT 2.80 GHz 44 1.00
Core™ i9 7940X 14 Cores + HT 3.10 GHz 44 1.00
Core™ i9 7920X 12 Cores + HT 2.90 GHz 44 1.00
Core™ i9 7900X 10 Cores + HT 3.30 GHz 44 1.00
Core™ i7 7820X 8 Cores + HT 3.60 GHz 28 1.00
Core™ i7 7800X 6 Cores + HT 3.50 GHz 28 1.00
*SKX-Refresh CPUs are supported with earlier BIOS versions, but recommended to update to 1.12 for best stability/overclock potential**Cascade Lake-X CPUs can boot into the BIOS with older BIOS versions, but will not function properly until updated to at least version 1.19
post edited by sparetimepc - 2020/02/12 02:34:46