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Nvidia Working on a CPU+GPU Combo
Max Romantschuk writes "Nvidia is apparently working on an x86 CPU with integrated graphics. The target market seems to be OEMs, but what other prospects could a solution like this have? Given recent development with projects like Folding@Home's GPU client you can't help but wonder about the possibilities of a CPU with an integrated GPU. Things like video encoding and decoding, audio processing and other applications could benefit a lot from a low latency CPU+GPU combo. What if you could put multiple chips like these in one machine? With AMD+ATI and Intel's own integrated graphics, will basic GPU functionality be integrated in all CPU's eventually? Will dedicated graphics cards become a niche product for enthusiasts and pros, like audio cards already largely have?" The article is from the Inquirer, so a dash of salt might make this more palatable.
- Memory Management Units. Even in microcomputers there are some (old m68k machines) that have an off-chip MMU (and some, like the 8086 that just don't have one).
- Floating Point Units. The 80486 was the first x86 chip to put one of these on-die.
- SIMD units. Formerly only found in high-end machines as dedicated chips, now on a lot of CPUs.
- DSPs. Again, formerly dedicated hardware, now found on-die in a few of TI's ARM-based cores.
A GPU these days is very programmable. It's basically a highly parallel stream processor. Integrating it onto the CPU makes a lot of sense.I am TheRaven on Soylent News
http://www.cap-lore.com/Hardware/Wheel.html
This is known as the wheel of reincarnation, and has come up several times in the last forty years of graphics hardware.
I am an old school programmer so I tend to use ints a lot. The sad truth if that float using SSE are as fast and sometimes faster than the old tricks we used to avoid floats!
Yes we live in an upside down world where floats are faster than ints some times.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
That's sort of the point of building them on the same die. You can't just run a wire to it, as it would be quite slow. Wires tend to have parasitic inductances and capacitances, so the setup and hold times on the lines would be too large to provide a benefit.
System RAM is SLOW compared to GPU RAM. PCIe actually allows very high speed access to system RAM, but the RAM itself is too slow for GPUs. That's one of the reasons their RAM amounts are so small, they use higher speed and thus more expensive RAM. Also because of the speed you end up dealing with cooling and signal issues which makes it impractical (or perhaps impossible) to simply stick it in addon slots to allow for upgrades.
Even fast as it is, it's still slower than the GPU would really like.
What you've suggested is already done by low end accelerators like the Intel GMA 950. Works ok, but as I said, slow.
Unless you are willing to start dropping serious amounts of cash on system RAM, we'll be needing to stick with dedicated video RAM here for some time.
Yes the SYSTEMS Tom used to test have normal speed ram for systems. Duh. The graphics cards, however, have much faster RAM. For example my system at home has DDR2-667 RAM. That's spec'd to run at 333MHz which is 667MHz is DDR RAM speak. My graphics card, a 7800GT, on the other hand has RAM clocked at 600MHz, or 1200MHz in RAM speak.
Not a small difference, really. My system RAM is rated to somewhere around 10GB/second max bandwidth (it gets like 6 in actuality). The graphics card? 54GB/sec.
Video cards have fast RAM subsystems. They use fast, expensive chips and they have controllers designed for blazing fast (and exclusive) access. You can't just throw normal, slow, system RAM at it and expect it to perform the same.