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Is there a difference between GDDR5 Effective Memory Clock vs GGDR3?


I am planning to build a desktop for gaming and entertainment. I was just looking at graphics cards and I am deciding between the Radeon HD 5770 1GB or buying my friend's Radeon HD 4850 512MB at a discount.

I was looking up the specs to compare both these cards and I noticed that the 5770 has a higher core clock than the 4850 and that the 4850 has a higher effective memory clock than the 5770. However, the 4850 has GDDR3 memory and 256-bit interface as opposed to the 5770's GDDR5 128-bit. I was just wondering which one is the better card? Does the memory clock have a bigger impact on how the card performs, or is that dependent on the core clock? (the 5770) (the 4850, a little out of date, but I can get it in good condition for a good price from my friend)
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  1. spec numbers are just that, numbers that don't really tell anything when comparing different architectures, try some reviews instead:

    thats a gts450 review, but the performance summary graphs have 4850 and 5770 in them as well. As You can see, the 5770 is some 20% faster than a 4850.
  2. The HD5770 beats the HD4850 hands down.
  3. Best answer
    A lot of this will depend on what you want to do with the card and the price your friend wants for the 4850. I would say half what the 5770 costs or forget it and get the 5770.
    The size of your monitor and which games you want to play would come into it as well but again teh price of teh 4850 would be relevant to the decision on that as well.
    As for your technical question concerning the memory types. Basically (simplified slightly) GDDR3 memory is Double Data Rate memory, which is what the DDR stands for.
    GDDR5 is somewhat different as it is effectively Quad Data Rate memory.
    This is why its only on a 128 bit bus as its cheaper to make a 128 bit bus. Because its running basically twice as fast as the GDDR3 its effectively the same thing as GDDR3 running on a 256 bit bus.
    That's a very basic explanation of it and while its basically right it is a little more complicated than that but for the layman it is basically correct.

    Let us know the rest of the system and we can help more. Personally i would always go with the newer tech unless you were getting the 4850 at a steal and your display was 19"

    Mactronix :)
  4. Thanks everyone for the suggestions! I really appreciate it. My friend was offering his 4850 for $80, but right now I'm leaning towards getting the HD5770. Mactronix, thanks for answering my technical questions, it helped a lot. And here is what my system is right now. This is actually my first build and I have everything except the video card--that was the part I was most confused on!

    CPU: Intel Core i5-750 Lynnfield 2.66GHz $190 [...] -_-Product

    Mobo: ASUS P7P55D LGA 1156 Intel P55 ATX Intel Motherboard $135 [...] llFullInfo

    Psu: OCZ Fatal1ty OCZ550FTY 550W $50 after MIR [...] 20fatal1ty

    Memory: CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM $78 [...] -_-Product

    Hard Drive: Seagate Barracuda 7200.12 ST31000528AS 1TB 7200 RPM Internal Hard Drive -Bare Drive $75 [...] -_-Product

    Case: COOLER MASTER Storm Scout $90 [...] -_-Product

    OS: Windows 7 Professional 64-bit (I already have this--got it from school for a discount!)

    I plan on running this system on my LG 24" monitor at 1920 x 1080 resolution.
  5. Mactronix: So basically if a GDDR5 was running on 256-bit, it would be twice as fast as GDDR3 running on 256-bit?
  6. waycool4690 said:
    Mactronix: So basically if a GDDR5 was running on 256-bit, it would be twice as fast as GDDR3 running on 256-bit?

    More or less yes. As i mentioned its a bit more complicated and there are some issues that mean its not quite X2 but near enough for explanation purposes without getting all techy and complicated
    Looking at your system specs i would say you may want to look at the GTX 460 1GB model take a look here

    Click on the reviews tab (Top left) and scroll down to find some of the various versions that are available. If its within your budget and you don't have an aversion to Nvidia you will see that it kills a 5770 stone dead.

    This is probably the best one

    Mactronix :)
  7. Just in case you were interested in the ins and outs of GDDR5,2845,2309870,00.asp

    Mactronix :)
  8. Best answer selected by waycool4690.
  9. This topic has been closed by Mousemonkey
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