Why does iGPU memory clock lower?

[Joduko]

I was comparing some APUs with benchmarks on Youtube and I notice the GPU memory is clocked at different speeds, all lower than the system memory that I thought integrated graphics utilized.

 

2200G seems to run at 1,467 MHz

 

3500U running at 1,200 MHz

 

A 3200G running at 1,600 MHz

 

An A10 5800K running at 1086 MHz

 

An Athlon 200GE running at 1,333 MHz

 

There are no benchmarks for the new 4750G APU in Planetside 2, but all the games I do see it tested in show its GPU memory clocked at 2000 MHz which is higher than all the others. If an APU uses system RAM how come the graphics memory doesn't clock as high as that? ie: 3200 MHz for a lot of popular RAM kits. From all these benchmarks it looks like the memory is faster as the APUs generally get newer, but since I'm a noob IDK why.

[Eigenvektor]

Quote

There are no benchmarks for the new 4750G APU in Planetside 2, but all the games I do see it tested in show its GPU memory clocked at 2000 MHz which is higher than all the others. If an APU uses system RAM how come the graphics memory doesn't clock as high as that? ie: 3200 MHz for a lot of popular RAM kits. From all these benchmarks it looks like the memory is faster as the APUs generally get newer, but since I'm a noob IDK why.

You're seeing the difference between actual physical clock speed and "effective" clock speed. Afterburner shows the physical clock speed, not the effective clock speed.

 

DDR RAM marketed as 3200 MHz is actually running at 1600 MHz. It can do two operations per clock cycle (DDR = double data rate), which means it is effectively as fast as regular RAM running at 3200 MHz. Which is also why some people prefer to talk about MT/s (transfers per second) rather than the actual clockrate.

 

~edit: Attempt to fix ridiculous post size, probably caused by quoting

[MAP_Finder]

2 minutes ago, Eigenvektor said:

My guess would be the difference between actual physical clock speed and "effective" clock speed. DDR RAM marketed as 3200 MHz is actually running at 1600 MHz. It can do two operations per clock cycle (DDR = double data rate), which means it is effectively as fast as regular RAM running at 3200 MHz. Which is also why some people prefer to talk about MT/s (transfers per seconds) rather than the actual clockrate.

This is very true, the readings your getting may be the clock speed of one data cycle, DDR RAM does clocks in two cycles so if that's the case double the numbers your getting to see what the overall clock speed of the RAM is. Also, I know that with extreme overclocks on LN2 at least, using the GPU is bad because it stresses silicone more then not using it. I doubt that's the case but if your getting lower CPU clock speeds then that could be part of it.

[Joduko]

12 minutes ago, Eigenvektor said:

You're seeing the difference between actual physical clock speed and "effective" clock speed. Afterburner shows the physical clock speed, not the effective clock speed.

 

DDR RAM marketed as 3200 MHz is actually running at 1600 MHz. It can do two operations per clock cycle (DDR = double data rate), which means it is effectively as fast as regular RAM running at 3200 MHz. Which is also why some people prefer to talk about MT/s (transfers per second) rather than the actual clockrate.

 

~edit: Attempt to fix ridiculous post size, probably caused by quoting

That's super interesting and I didn't know that. Thank you.