4870 Overclocking Thread

[dejanh]

How do you explain that Diamond HD4870 XOC BE artifacts right out of the box @ 800 Core ?

I'll chime in on this being that I'd be the XOC BE resident expert

(1) Stock cooling.
(2) No voltage increase on either the core or the memory.
(3) The memory clock is too high for no voltage increase as the Qimonda 40X chips are rated up to 4GHz but are running at 4.4GHz on the XOC BE (10% OC). They have another set (50X) that is rated up to 5GHz but unfortunately no 4870s are blessed with that one.
(4) Lowering the clocks of the memory to 1050 or so on the XOC BE will leave it stable at 800 core.

General comment is that if you want 100% stability with literally zero artifacts ever with any 4870s you need to up the volts for any clocks higher than 820 core and about 1050 memory. That was my finding so far having worked on a number of these cards. Furthermore, voltages over 1.35V-1.37V will make your card very unstable because of a number of possible reasons...VRMs too hot, OCP kicking in, OVP kicking in.

Don't expect to gain much in performance by overclocking the card. As much as some people may bash me for saying this, the 4870 is not the best and fastest card out there by a long shot, and it is a rather poor overclocker with very mixed results and success rates. Everybody's jaw drops though at the thought of GDDR5 and how high it can go, but the point is missed that the limitations of this card do not come from its memory which has more than enough bandwidth to feed the card even at 3.4GHz but rather the core. One thing to note however is that this is probably the best performance/$ card out there following the 4850.

if you're talking about Crysis, try the 8.8 beta driver. i heard some people were having problems with Crysis that were solved with the new driver. if you're talking about other games, just return your card for a refund. no need to put up with artifacts.

XOC BE has problems out of the box with everything. But I posted lots about this already so no need to reiterate And yeah, refund is the best option.