i have an AMD a8 3870k apu and a Sapphire HD6670, which i want to be working in Dual Graphics for improved performance. but i can't tell if it's working properly, as it seems to perform worse than just the 6670 alone..
AMD a8 3870k 3,0GHz/ radeon 6550d
Asus F1A75V-Pro (discrete graphics card in top Pci-e slot)
Sapphire Radeon HD6670 1GB GDDR5
Geil 8GB 1866GHz CL10 1,65V
Crucial M4 128GB
Catalyst 13.2 (issue was the same with all previous Catalyst versions)
Bios american megatrends 2302, updated to most recent version
recent clean Windows 7 64bits ultimate install, with SP1
in AMD Vision Control Centre, i can choose to run the gpu's in Dual Graphics (1), or just the 6670 card alone (2)
in (1), WEI score is just 6,8 and 3DMark Fire Strike gives a 1025 score.
in (2), WEI is 7,1 and 3DMark Fire Strike is 1340
so when i put the cards in Dual Graphics, performance drops significantly! also there is never the dual graphics logo, that is supposed to be onscreen, when heavily using dual graphics mode fullscreen. this logo is enabled somewhere in the Catalyst control center.
one possible source of the problem might be this: my Sapphire Radeon 6670 uses GDDR5 memory, while the RAM (used by the apu's 6550d) is DDR3. it isn't perfect, but i wouldn't think this causes the huge drop in performance. but maybe i'm wrong, and this GDDR5/DDR3 difference is really important/causing serious lower performance..
can anyone verify this? i do not have a Dual graphics-compatible GDDR3 card available for testing.
thanks in advance, freduce
all clock/memory speeds are stock for the gpu's:
800MHz gpu/933MHz memory for the 6550d
800MHz gpu/1000MHz memory for the 6670
maybe is there some problem here?