I decided to order an Accelero s1 Rev2 for my Sapphire 4870 after seeing what my temps were on the core and mem. I placed my order then decided to read a few more reviews on this product then i found myself reading nothing but horror stories about this cooler and the 4870.
I was horrified and was one click from cancelling my order but it was to late. The cooler was on the way, so i sat anxiously waiting for my $25.00 paper weight. When it arrived i decided to go ahead and give it a go since i love messing around with my pc, these are my results.
770 core / 1000 mem (stock voltages, stock cooler)
Core Idle - 55 C
Vdimm Idle - 63 C
Core Load - 75 C
Vdimm Load - 93 C
813 core / 1050 mem (stock voltages, accelero s1 Rev2)
Core Idle - 42 C
Vdimm Idle - 50 C
Core Load - 56 C
Vdimm Load - 61 C
Before the accelero s1 Rev2 was installed my max core clock was 770 w/o getting game crashes, after the new cooler was installed 813 core was easily achieved and possibly more with volt modding.
Nice to know that you are now happy with your purchase.
I was actually considering attaching the S1 rev2 to a HD 4890, but I think I'm just gonna upgrade to a HD 4770 and wait for DX11 card at a relatively good price. At that point the HD 4770 will simply go into my HTPC.