AMD Publishes Mobile Kaveri Specifications

36 Comments

View All Comments

• monstercameron - Monday, May 26, 2014 - link

  that seems like a possible trade of between board complexity and space requirements for more memory channels or higher power consumption for higher clocks.

• MikeMurphy - Monday, May 26, 2014 - link

  They are already dual channel, one channel per DIMM slot. Only larger laptops allow for 4 memory modules, though, due to space constraints (and probably power consumption penalty). These days with 8GB DIMMs commonplace the need for 4 memory slots is long past. I expect 16GB ought to be enough for 99.9% of the users out there.

• Drumsticks - Monday, May 26, 2014 - link

  Hell, 8GB is good enough for 98% of users, and 4GB is good enough for 90% of them :P

• TheinsanegamerN - Monday, May 26, 2014 - link

  It's not a matter of capacity, but rather memory bandwidth. four 4GB 1600 memory modules would provide 51.2 GB/s theoretical throughput, whereas two 8GB 2133 memory modules only supply a theoretical 34.2GB/s. This bandwidth problem is why the iris pro had dedicated cache memory, to take some load off of the primary memory bus.

• Alexvrb - Monday, May 26, 2014 - link

  You don't understand. As Mike tried to point out, AMD already HAS dual memory channels on these chips (and has for years!). Only their lowend/low power chips have single channel, such as Beema/Mullins and their predecessors. The number of memory slots doesn't dictate bandwidth without additional channels in the processor. Desktop AMD systems with 4 memory slots... guess what? Still two channels! Same bandwidth potential whether you populate 2 or 4 slots with memory sticks... actually maybe a bit less with 4 since it's harder to hit the same speeds when clocking aggressively.
  
  What you're REALLY asking for is quad channel, which is silly for many reasons (I won't get into all of them like chip redesigns). Suffice it to say it would only generally fit in very large laptops (17"+) and it would be far better to just slap a seperate graphics chip in there - whether you go dual graphics or not, the discrete graphics will wipe the floor with a quad channel integrated GPU solution - and cost about the same.
  
  What I'd really like to see tested is an FX-7600P rig with a 512+ shader Cape Verde GDDR5 chip paired in dual graphics.

• Kevin G - Tuesday, May 27, 2014 - link

  With DDR4 on the horizon, this will change shortly. Consumer chips will likely only support one DDR4 DIMM per channel. Only server parts that'll support registered memory will be able to support two or three DIMMs per channel. Oh, and with DDR4's point-to-point nature, adding more DIMMs could reduce performance since to reach the second DIMM the signal has to be propagated through the first DIMM (similar to how FB-DIMMs worked).

• TheinsanegamerN - Tuesday, May 27, 2014 - link

  "What you're REALLY asking for is quad channel, which is silly for many reasons (I won't get into all of them like chip redesigns). Suffice it to say it would only generally fit in very large laptops (17"+) and it would be far better to just slap a seperate graphics chip in there - whether you go dual graphics or not, the discrete graphics will wipe the floor with a quad channel integrated GPU solution - and cost about the same."
  considering AMD's driver issues getting dual graphics to work, no, id rather have just the integrated.
  also, i dont see what is so rediculous about quad channel. heck, the APU itself references already HAVING two more channels for ddr5, but AMD wont use them
  http://www.anandtech.com/show/7702/amd-kaveri-docs...
  why AMD would cut them out is beyond me, but is it so much to ask for them to use the entire package? considering their previous mobile offering were....poor, seeing as how their "superior" gpus were only a hair faster then intel's. I want a competitive chip, not a neuteered, held back mobile chip.

• Alexvrb - Wednesday, May 28, 2014 - link

  The latest iterations of dual graphics aren't horrible, they're improving with every generation. However, if you'll read what I said, even if you disabled dual graphics the discrete GPU is better.
  
  Anyway, to add quad channel means a new memory controller, new socket, new chip, higher thermals/power, etc. Not to mention it would only see use in a few systems, most OEMs are going to use a single/dual channel setup for cost and space reasons. So the quad-channel chips would hardly see any use. Why should AMD bother with a third design, when OEMs can just drop in discrete graphics?
  
  Here let me rephrase things: Discrete GPU with GDDR5 @ 128-bit+ interface > Equivalent Integrated GPU with quad-channel DDR3. There's no getting around that, even if you ignore all the other factors.

• TheinsanegamerN - Tuesday, May 27, 2014 - link

  also, in what universe does having four sodimms take a 17 inch laptop, but 2 sodimms and a dedicated gpu with its own vram fits into a 14 inch laptop?

• Alexvrb - Wednesday, May 28, 2014 - link

  Regardless of channels, how many laptops do you see with 4 memory slots? Are there technical reasons for this beyond space? Yeah, probably. But it doesn't matter. The fact is that if you want that many RAM slots it probably isn't going to happen on a smaller system.