This might be a kind of stupid question but I was always wondering this. Why don't RAM producers use GDDR5 RAM chips in their sticks? It would boost performance especially APU's. Is it a question of cost? Thanks.
Why is it not possible to use GDDR5 as regular RAM?
noobhell
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No, that number at the end is important. They correspond to a different specification add or modifying features and design requirements.
Unfortunately, you have to be a JEDEC member to find out exactly what the differences are:
http://www.jedec.org/standards-documents/results/taxonomy%3A4229
http://www.jedec.org/standards-documents/docs/jesd-79-3d
Because they are different technologies. While they do have similarities and share some design features, they are distinctly different. It would be like trying to use a modern AMD CPU in a Intel socket..... sure, both are x86 CPUs with multiple levels of cache, support OoOE, do power/clock gating, etc.Originally Posted by noobhell
This might be a kind of stupid question but I was always wondering this. Why don't RAM producers use GDDR5 RAM chips in their sticks? It would boost performance especially APU's. Is it a question of cost? Thanks.
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No, GDDR5 and DDR3 are different.Originally Posted by Cavi Mike
GDDR5 RAM is DDR3 RAM just optimized for graphics - hence the "G." The number at the end means nothing.
No, that number at the end is important. They correspond to a different specification add or modifying features and design requirements.
Unfortunately, you have to be a JEDEC member to find out exactly what the differences are:
http://www.jedec.org/standards-documents/results/taxonomy%3A4229
http://www.jedec.org/standards-documents/docs/jesd-79-3d
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But why don't AMD and Intel start producing northbidges which support GDDR5? Especially for AMD it would be beneficial.Originally Posted by DuckieHo
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Because they are different technologies. While they do have similarities and share some design features, they are distinctly different. It would be like trying to use a modern AMD CPU in a Intel socket..... sure, both are x86 CPUs with multiple levels of cache, support OoOE, do power/clock gating, etc.Originally Posted by noobhell
This might be a kind of stupid question but I was always wondering this. Why don't RAM producers use GDDR5 RAM chips in their sticks? It would boost performance especially APU's. Is it a question of cost? Thanks.
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However, AMD and Intel IGP is now on die and no longer in a seperate off-package chip.
AMD has included an option for SidePort memory. This is sometime implemented as dedicated DDR3 for the chipset IGP.Originally Posted by noobhell
But why don't AMD and Intel start producing northbidges which support GDDR5? Especially for AMD it would be beneficial.
However, AMD and Intel IGP is now on die and no longer in a seperate off-package chip.
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Or would the IO on a DDR3 stick be different then on a stick with GDDR5? Because in this wikipedia article it says GDDR5 is based on DDR3.
What I mean is why don't they make GDDR5 memory support in their chipsets. Then RAM producers could then stick GDDR5 memory modules onto their RAM-sticks and then you could use ultra fast RAM. I know APUs include the GPU on the die and not in the chipset, but the GPU will still be using the system RAM as a frame buffer making GDDR5 the ultimate choice.Originally Posted by DuckieHo
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AMD has included an option for SidePort memory. This is sometime implemented as dedicated DDR3 for the chipset IGP.Originally Posted by noobhell
But why don't AMD and Intel start producing northbidges which support GDDR5? Especially for AMD it would be beneficial.
However, AMD and Intel IGP is now on die and no longer in a seperate off-package chip.
Or would the IO on a DDR3 stick be different then on a stick with GDDR5? Because in this wikipedia article it says GDDR5 is based on DDR3.
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The increased complexity and price is not worth the benefit. If someone wanted more performance out of an iGPU... they wouldn't be using an iGPU. Why spend $50 for a specialized 1GB GDDR5... or just get a $50 better discrete video card?
Yes, it is "based on" but this is not the same as "is".
Again... AMD/Intel chipsets today are only for storage and PCIe devices. The memory controller and iGPU are on-die with the CPU. Adding another memory controller is expensive.Originally Posted by noobhell
What I mean is why don't they make GDDR5 memory support in their chipsets. Then RAM producers could then stick GDDR5 memory modules onto their RAM-sticks and then you could use ultra fast RAM. I know APUs include the GPU on the die and not in the chipset, but the GPU will still be using the system RAM as a frame buffer making GDDR5 the ultimate choice.
Or would the IO on a DDR3 stick be different then on a stick with GDDR5? Because in this wikipedia article it says GDDR5 is based on DDR3.
The increased complexity and price is not worth the benefit. If someone wanted more performance out of an iGPU... they wouldn't be using an iGPU. Why spend $50 for a specialized 1GB GDDR5... or just get a $50 better discrete video card?
Yes, it is "based on" but this is not the same as "is".
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The short answer(as DuckieHo) have already provided the long answer:
You need a GDDR5 compatible IMC on the CPU itself & a Socket with Pins that support this IMC for the CPU to utilize GDDR5 Ram. AMD/Intel CPU's IMC currently is only compatible with DDR3 Ram.
You need a GDDR5 compatible IMC on the CPU itself & a Socket with Pins that support this IMC for the CPU to utilize GDDR5 Ram. AMD/Intel CPU's IMC currently is only compatible with DDR3 Ram.
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A GDDR5 memory controller could be integrated onto a CPU, but it would take a huge amount of die area to support any significant quantity of memory at significantly higher speeds than DDR3 is capable of now. This would obviously require new CPUs and probably a new socket. The memory itself would also cost a fortune.
Chipset hasn't had anything to do with memory since socket 462 on AMD and LGA-775 on Intel.Originally Posted by noobhell
What I mean is why don't they make GDDR5 memory support in their chipsets.
A GDDR5 memory controller could be integrated onto a CPU, but it would take a huge amount of die area to support any significant quantity of memory at significantly higher speeds than DDR3 is capable of now. This would obviously require new CPUs and probably a new socket. The memory itself would also cost a fortune.
GDDR5 is optimized for max data bandwidth, but it is not stable enough to be used as RAM. VRAM error and you might get a weird pixel, where as if the same happened to RAM you'd bsod / crash. Not that i'd be expert on the subject, but it was featured on Linus livestream
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There are professional GPGPU / HPC cards, as well as coprocessors, that use GDDR memory for mission critical tasks.
Also, you can stress test consumer GPU memory and demonstrate it's comparable relative stability.
GDDR is just as stable as normal DDR.Originally Posted by Fulvin
GDDR5 is optimized for max data bandwidth, but it is not stable enough to be used as RAM. VRAM error and you might get a weird pixel, where as if the same happened to RAM you'd bsod / crash. Not that i'd be expert on the subject, but it was featured on Linus livestream
There are professional GPGPU / HPC cards, as well as coprocessors, that use GDDR memory for mission critical tasks.
Also, you can stress test consumer GPU memory and demonstrate it's comparable relative stability.
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You have to remember that DDR3 was $100 per GB only a couple of years ago, my first GPU card had 320MB of DDR5 and twice as much cost a lot more....
1. It WAS too expensive.
2. They didn't need the speed.
3. They couldn't afford to jump two generations of memory technology for no reason.
All IMHO
dunx
P.S. Found on the net....
November 4, 2009 at 12:29 am
Wish I were finding this to be true. DDR3 is rising…fast. I am a small custom PC builder and it is quickly becoming a worry in my builds. I have read that this is perhaps due to the release of Windows 7, and that as excitement wanes, so might the prices.
One high end DDR3 model I had been using has risen from around $170 to $245 for 6Gb DDR3 1600 in the last 60 days. Another model I was using that had retailed for around $110, is now costing between $160-170 wholesale for 6Gb DDR3 1600.
1. It WAS too expensive.
2. They didn't need the speed.
3. They couldn't afford to jump two generations of memory technology for no reason.
All IMHO
dunx
P.S. Found on the net....
November 4, 2009 at 12:29 am
Wish I were finding this to be true. DDR3 is rising…fast. I am a small custom PC builder and it is quickly becoming a worry in my builds. I have read that this is perhaps due to the release of Windows 7, and that as excitement wanes, so might the prices.
One high end DDR3 model I had been using has risen from around $170 to $245 for 6Gb DDR3 1600 in the last 60 days. Another model I was using that had retailed for around $110, is now costing between $160-170 wholesale for 6Gb DDR3 1600.
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