Hi guys, was just wondering. It's obvious from this thread that the 4870 is a better deal for the 4890. But I'm thinking there must be a reason why ATI came out with the 4890 in the first place right? What's a good reason for choosing the 4870 over the 4890? When you need to maximize a larger display perhaps? Appreciate any thoughts.
My feelings are that ATI created the 4890 to have a single-GPU card at both a performance and price point somewhere in-between it's 4870 and 4870X2, as the difference between those two cards is truly significant. I specifically said "single-GPU card" because it can easily be argued that the 4850X2 was already filling those price and performance points. The question that needed answering was, how successfully was the 4850X2 filling the gap? With only one manufacturer making them - Sapphire - the 4850X2 was often overlooked by the general public. Also, since the 4850X2 must use CrossFire technology to function, it's performance across all games is not linear by any means. So, ATI went about creating a single-GPU solution to fill that gap, perhaps even to specifically combat nVIDIA's own "price gap-filling" single-GPU card, the GTX275.
I think you're right on track when you mention the 4890's main user-related purpose being to maximize a larger, higher resolution display. However, with most gaming benchmarks only showing the 4890 approximately 10% more powerful than a 4870 1GB card, one has to wonder, is 10% of 30 or 40 FPS really worth the additional cost? In the systems of power-users who feel every frame counts, the cost difference is well worth it. To more price-conscious users, it is not.
The HD 4890 is a "refreshed" HD 4870 that is part of AMD/ATI's production cycle. nVidia also "refreshes" their products as well. It all boils down to competition.
Is it worth buying a HD 4890 over a HD 4870? Maybe, maybe not. The HD 4870 is the better bang for the buck right now, but as time passes the price on the HD 4890 will come down as well. As Fullmetall has stated, the HD 4890 offers better OC'ing capabilities, but if you don't like OC'ing, then it's a non-issue.
Personally, I was gonna buy an HD 4890, but I might buy the HD 4770 as a "temporary" upgrade to my X1900XT. Based on preliminary benchmarks, the HD 4770 is expected to come within 5% - 10% of a stock HD 4850's performance (depending on the game). When OC'ed, the performance is expected to be between the HD 4850 and HD 4870, not bad for something that is expected to sell for $99. But the devil is in the detail, so I will wait for the HD 4770 to be officially reviewed before making my decision.