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Old January 11, 2012, 01:09 PM
jumpload jumpload is offline
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Agreed JJThomp and im generalizing in a big way with ball park numbers, none the less the real world performance gains vs what the effective memory speed is trying to tell us, is so far off the mark is laughable

Sadly if you try and read up on the topic your bombarded with over kill statical information and in most cases this acts as a choke to conceal the real facts.

The real facts being that memory bandwidth has improved over time but at the expense of reaction times,meaning latency and in many cases the wight paper numbers performance wise aren't even close to real world speed gains seeing as only favorable statical information is used to calculate the speed gain with a side order of BS and it doesn't take in the hole picture.

What their trying to do really best i can tell to improve bandwidth is that their doing the same thing as raid for hdd only this time raid for ram chips but in so doing latency gos through the roof.

Remember you can't see the memory timings on a video card ram and its not talked about much.

Same deal with single channel vs duel vs triple vs quad

Single channel VS Duel channel last i checked = 30% performance gain {ballpark number} not +100%~2x and latency jumps, though maximum throughput improves and the memory channels become independent up to a point.

And its all down hill from their.

This could all so explain why cash ram on cpu's has exploded in size as well.
Best guess~ its to keep the cpu from stalling when it requests more data from main system ram and has to wait for the data to come in.

In the mean time it just works with the data in the cash ram as it waits.
Think of this like having the option to increase your download bandwidth as much as you want but at the same time the more bandwidth you have the higher your ping gets.

In the case of gpu~cpu that translates in to a performance loss.

Just try and play a online game with a ping in the 5000 zone, good luck and it wont mater if your bandwidth is 3000 Mbps seeing as client side your software has to wait for the data to come in before it knows what to do next.

Meanwhile the player with a ping in the 50 zone with 1 Mbps is owning you.

Its a trade off, and the way things are going im starting to wonder if we will see the day were cpu cash ram that isn't integrated once more reappears on the market just like in the old 486 computer days were you had your level 2~3 cash ram on the mobo and not on the cpu it self.

think of this like level 2 main system ram {high speed single channel ~ large memory bus bit width}
or level 4 cash ram for i7.
128 megs 2000mgz real world speed + dedicated ram to cpu + 512 bit bus + proprietary ram anyone ?

example of level 2 cash ram on a old 486 computer


xbox 360 gpu + off die hipper cash ram.




Note: they moved on at this point last i checked to more then one memory bus channel for the interconnect to the ram to the memory controller on video cards.

And ill check up after if that was the case as well in the past on some video cards.

Last edited by jumpload; January 14, 2012 at 05:31 AM. Reason: added xbox gpu pic and info
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