885 will give you 877.5. Just tried it myself with Riva Tuners own hardware monitoring. The core will only increase in 13.5 increments. So 864, 887.5, 891, 904.5. Not sore if this is bios controlled or not. So even if you try 890 you'll still get 877. Hit 900 and you'll get 891, etc. Haven't checked how the memory increments.