based on jimmyh's cod4 benchmark:
(compute power to bandwidth ratio)
memory:
4870 speeds / 5870 equivalent / FPS / % increase
750 / 530 --- 850 / 1200 ----- 100 --- 0%
750 / 575 --- 850 / 1300 ----- 104 --- 4%
750 / 618 --- 850 / 1400 ----- 107 --- 2.9%
750 / 663 --- 850 / 1500 ------ 112 --- 4.6%
750 / 900 --- 850 / 2040 ------ 121 --- n/a
core:
4870 speeds / 5870 equivalent / FPS / % increase
750 / 530 --- 850 / 1200 ------ 100 --- 0%
800 / 530 --- 906 / 1200 ------ 103 --- 3%
750 / 575 --- 850 / 1300 ----- 104 --- 0%
800 / 575 --- 906 / 1300 ----- 107 --- 2.9%
835 / 575 --- 946 / 1300 ----- 110 --- 2.8%
http://www.xtremesystems.org/forums/...7&postcount=88

Lightman's 3d06 benchmark:
core / mem / FPS / + fps / + %
850 / 3600 / 091.7 / 0 / 0%
850 / 4000 / 095.2 / +3.5 +3.8%
850 / 4400 / 097.9 / +2.7 +2.9%
850 / 4800 / 100.3 / +2.5 +2.5%
850 / 5200 / 102.4 / +2.1 +2.1%
http://www.xtremesystems.org/forums/...1&postcount=23

Extrahardware.CZ Crysis 1920 × 1200, 4× AA
core / mem / fps / +fps / +%
memory:
850 / 4400 - 40,9 - 0 / 0%
850 / 4800 - 42,0 - +1.1 +2.7%
850 / 5200 - 43,1 - +1.1 +2.6%
core:
785 / 4800 - 40,1 - 0 / 0%
850 / 4800 - 42,0 - +1.9 +4.7%
915 / 4800 - 43,2 - +1.2 +2.9%
core and memory:
785 / 4400 - 39,3 - 0 / 0%
850 / 4800 - 42,0 - +2.7 +6.9%
900 / 5200 - 44,7 - +2.7 +6.4%
http://www.extrahardware.cz/pretakto...adeonu-hd-5870

Firingsquad Crysis 1920 × 1200, 2× AA
core / mem / fps / +fps / +% (from stock)
850 / 4800 - 31.6 - 0 / 0%
850 / 5272 - 32.3 - +0.6 +2.2%
850 / 4800 - 31.6 - 0 / 0%
930 / 4800 - 33.1 - +1.5 +4.7%
850 / 4800 - 31.6 - 0 / 0%
930 / 5400 - 34.3 - +2.7 +8.5%
http://firingsquad.com/hardware/ati_...king/page5.asp

Meh. You can get gains from overclocking core, or memory, or both together. You get higher gains (usually) from overclocking the core. Only in the game Batman did firingsquad get higher performance from overclocking memory vs. core. Conclusion: overclock core & memory as much as possible. Memory bandwidth isn't the bottleneck, otherwise we would have relatively no gain from core overclocking...?
Quote Originally Posted by JimmyH View Post
Can't help thinking that the impressive power consumption of this card is actually could be the shaders sitting around doing nothing.
Yeah seems like it... jeez.