ATI Radeon HD 4870X2 vs. ATI Radeon HD 4850

[Unequaled]

Actually I need a comparison between these two graphic cards: ATI Radeon HD 4870X2 and ATI Radeon HD 4850. I am thinking of buying a new graphic card for my system, but I am confused between ATI Radeon HD 4870X2 and ATI Radeon HD 4850. Currently I am having gigabyte motherboard and AMD processor. I have done research on my part to find the best graphic card and finalized to two graphic card for my gaming pc. I have the idea that these two graphic cards are really good but which is the best between these two. So I need comparison between these two graphic cards.

[Jacek]

Best in between these two is ATI Radeon HD 4870X2. The ATI Radeon HD 4870 X2, code-named R700, which refers only due to the GPU. Because on the 3D accelerator finally two RV770 GPUs are used, which were unchanged from the Radeon HD 4870. Thus, they are heavily depending 965 million transistors and manufactured by TSMC in the modern 55-nm process. Thus, each GPU has also its own VRAM, depending on the 1024 MB. The two RV770 GPUs on the dual-GPU card can be controlled with 750 MHz, while the GDDR5 memory is operated at 1,800 MHz. So are the clock speeds are identical to a conventional Radeon HD 4870. Despite some enthusiastic sounding rumors ahead of today's product idea is using the Radeon HD 4870 X2 CrossFire continue to conventional technology. In consequence, there are three different rendering modes (AFR, Scissor and Super Tiling), where (the geometry can also be accelerated by the second GPU) in current games based on the best scaling only AFR is used.

[Chandranath]

Besides the benefits of AFR does it logically also its weaknesses. Then every GPU in its own VRAM can access the same data, so both 1,024-MB memory can be filled with single bits. Therefore can be used effectively only 1,024 MB, 2,048 MB although physically be installed. In addition, one cannot logically include all execution units in the chips twice, since some calculations occur twice and also play a role in latency. Not to mention the problem of "micro stuttering" which can reduce heavily in low FPS areas of the game is fun - then read more. As on the ATI Radeon HD 3870 X2 uses the Radeon HD 4870 X2 a special PCIe switch to split the incoming PCIe x16 signal of the second generation of the two GPUs. This switch is again from PLX and goes by the name "PEX 8647". Thus, it is a PCIe switch to the second generation who can manage a total of 48 PCIe lanes (GENRATION 2). The incoming 16 PCIe lanes divided on the PEX 8647 x16 on two signals and forward them to the two RV770 GPUs. Thus, there is no loss of bandwidth, even though the motherboard can provide on a slot only 16 lanes available. The switch measures a size of 27x27 mm and requires low 3.8 watts during operation. The predecessor to the Radeon HD 3870 X2 is 4.9 watts more power hungry and also offers support for only one PCIe Generation 1.

[xanix]

In an architectural drawing of the memory controller of the RV770 chips fell our launch review of the Radeon HD 4850 is an entry called "CrossFire X Interconnect" on. We suspected that this only with a dual-GPU card is used, what ATi on demand also confirmed. However, we were absolutely with our speculation about the meaning of this compound next to it. Thus offers the crossfire X Interconnect, the ATi now "Side Port" calls only and alone at a higher bandwidth with ten additional gigabyte per second, that the two RV770 GPUs can communicate directly with each other. The memory of the other GPU you can use with this technology does not continue. Thus, the total internal bandwidth between the GPUs and the PCIe switch on the Radeon HD 4870 X2 at 20 GB / s (4 x five GB / s, 2 x five GB / s of it by the side port), while the Radeon HD 3870 X2 just five GB / s can be transferred (2 x 2.5 Gb / s). However, the additional 10 GB / s still not through the side port using the latest drivers on the Radeon HD 4870 X2 activated, so the bandwidth currently "only" in ten GB / s content. Since current applications is from a wider range, according to ATi cannot yet benefit will enable you the feature until next application as well as a future Catalyst driver.

[DoleBobSLI]

you should really just get 2 5770's for about the same price, you would have a bigger timeline before having to upgrade your gfx cards