Memory Bandwidth

Posted By: Michael Thomas - 10:51:56 Mon, May 22, 2006

Short Version

The speed at which the card can access memory.

Long Version

Memory bandwidth is equal to the size of the memory bus multiplied by the speed at which the memory is clocked.

The higher the memory bandwidth, the better the card will be able to handle large textures and anti-aliasing and anisotropic filtering. Not to say that you don't need a lot of memory bandwidth if you don't want to use these features, you still do. Memory bandwidth is important in nearly every part of graphics processing.

The amount and speed of the memory matter very little in comparison to the overall memory bandwidth. If you want a card with good memory, this number says it all.

8 Comments

Sunday, December 31, 2006 5:47:18 PM

Woejrs
guest

Are the terms memory bandwidth, memory transfer rate and memory bus speed synonymous?

Tuesday, January 02, 2007 1:17:38 PM

Mike
GPUReview Founder

Memory bandwidth and memory transfer rate mean the same thing. They both refer to how many bits of data can be pulled from memory per second. Memory bus speed is different, it refers only to the rate at which the bus operates. Since the memory bus is more than 1 bit wide, and (depending on how you look at it) can access more than one bit per clock with DDR, the 'memory transfer rate' doesn't tell the whole story.

Wednesday, June 06, 2007 7:29:30 AM

mostafa007
guest

hmmm , i found that the 8800GTX has less memory bandwidth than the HD 2900 XT , and 8800GTX is still faster , any one know why ?!

Friday, June 08, 2007 8:34:05 PM

gonX
guest

mostafa007, memory speed is not all that matters in graphics speed.

Actually it's the least influencing thing of everything.

Saturday, June 09, 2007 6:18:09 AM

anonymous
guest

@mostafa007 - The 8800 GTX's architecture is more efficient than on the HD 2900 XT and it has more pixel fill rate and texture fill rate than on the HD 2900 XT . The HD 2900 XT can theoretically match the 8800 GTX or come close to it . BUT since the HD 2900 XT requires VERY efficient drivers to work fast , currently it's not running at it's full potential

Friday, October 05, 2007 7:03:27 AM

ClashX
guest

Intersting to know that HD2900XT is far behind 8800GTX after this many driver releases. This shows even at its full potential HD2900XT is and will not ever be no match for 8800GX no matter howmany driver releases you are willing to wait for to happen.

Saturday, October 06, 2007 8:23:00 AM

anonymous
guest

3dmark06 shows the 2900xt's potential with completly optimized drivers. Unfortunatly it doesnt include AA which makes en enourmous hit on the r600.

Sunday, December 16, 2007 12:03:45 AM

wyz135
Senior Member

Radeon HD2900XT 1GB GDDR4 version have 128GB/s, which is currently the highest, but 8800 series is better, doesn't seems to make sense

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