64 bit GPU vs 128 bit gpu

[Jerry Jose]

Please sort out the differences between a 64-bit and 128-bit gpu...Also is the memory bandwidth an important factor in a GPU ???

 

[Novuake]

Do not look at specs, take the card model number, google it and check performance benchsmarks for that card.

Comparing specs is pointless.

 

[smorizio]

think of it as a highway. a two lane road can hold a set amount of cars per time. a 4 lane road can hold twice as many cars in the same time. so a 64 bit card can do 64 bits on a clock cycle a 128 bit can do twice as much per the same clock cycle. so if you had two gpu with the same gpu chip but one was 64 bit and the other had 128 bit bus the card with the larger bus would be faster.

 

[i7Baby]

Memory bus can be thought of literally as lanes of traffic. More lanes dedicated for traffic, the greater the flow. The graphics processor is connected to the RAM on the card via a memory bus.

As far as affects on gpu memory bus, I've seen mixed results. A wider bus doesn't simply mean the card is faster or will perform better.

 

[Cons29]

about bus width, a simple way to compute it (just to show the difference) is:
mem speed * bus width, so

if you have say same speed, say 100 (to keep it simple). then the memory bandwidth for both will be:
100*64(bit) = 6400
100*128(bit) = 12800

so, if you have a 64 bit, and everything being equal. the 64bit will have to have the mem speed up to twice (2*100) to be able to match the 128bit
200*64 = 12800 (to match 100*128)

these 64bit gpu's don't really have twice the speed of their 128bit counterpart, so those are usually slower. mem bandwidth is important but it's just one piece of the puzzle, and is more important than the amount of ram in most cases

 

[Jerry Jose]

about bus width, a simple way to compute it (just to show the difference) is:
mem speed * bus width, so

if you have say same speed, say 100 (to keep it simple). then the memory bandwidth for both will be:
100*64(bit) = 6400
100*128(bit) = 12800

so, if you have a 64 bit, and everything being equal. the 64bit will have to have the mem speed up to twice (2*100) to be able to match the 128bit
200*64 = 12800 (to match 100*128)

these 64bit gpu's don't really have twice the speed of their 128bit counterpart, so those are usually slower. mem bandwidth is important but it's just one piece of the puzzle, and is more important than the amount of ram in most cases

Thank you for that explanation.Can you please explain to me in detail regarding all of the factors affecting GPU performance and the relation between various factors....

 

[i7Baby]

If its hot, the GPU won't work as well.

If the GPU has more stream processors or cuda cores, it will perform better.

If the GPU uses faster memory, it will perform better.

If it has more memory, it will perform better too - especially with higher resolution monitors.

If the GPU has high clock speeds it will perform better.

 

[Cons29]

about bus width, a simple way to compute it (just to show the difference) is:
mem speed * bus width, so

if you have say same speed, say 100 (to keep it simple). then the memory bandwidth for both will be:
100*64(bit) = 6400
100*128(bit) = 12800

so, if you have a 64 bit, and everything being equal. the 64bit will have to have the mem speed up to twice (2*100) to be able to match the 128bit
200*64 = 12800 (to match 100*128)

these 64bit gpu's don't really have twice the speed of their 128bit counterpart, so those are usually slower. mem bandwidth is important but it's just one piece of the puzzle, and is more important than the amount of ram in most cases

Thank you for that explanation.Can you please explain to me in detail regarding all of the factors affecting GPU performance and the relation between various factors....

well, i am not really an expert. but here's what you can do, read reviews (they explain it there esp if the architecture is new) and you will learn a lot. also, ask before buying, do research before buying. check reviews, benchmarks, youtube etc.
we all start from not knowing much

 

[Jerry Jose]

Thanks a lot guys...