5 ms·
Something I like thinking about: Your computer can (probably) perform a few dozen arithmetic operations or a few stores/reads in the time light leaving your mon
by yan 16y ago
Something I like thinking about: Your computer can (probably) perform a few dozen arithmetic operations or a few stores/reads in the time light leaving your monitor takes to reach your eye balls.
edit: not to mention GPUs
- kjuhygtfrde 16y agoI wasted most of the early 90s doing that. We need 64 transputers to run this in real time, 1 year of PCB layout later = hey we can do this in 16 transputers and a Sparc. Cue another year of redesign - now it would only take 4 transputers and a Sparc5. Then a sales guy turns up promising to put the 16 transputers into an FPGA card. Just before that works we get an i860 board for the Sparc. Then finally we can do it in software on a Pentium...
- arethuza 16y agoAround '94 I used a close to the top of the range (at least in CPU power) DEC Alpha workstation - which I used for running Lisp programs. One of the other research teams in the department were working on some kind of custom chip for some specialized application and they wanted to show how much better it was than even the best commodity CPU so they gave me a chunk of completely unoptimized vanilla C to compile and run as a benchmark. Turns out the Alpha was way faster than their chip - which I don't think they were too happy about!
- woadwarrior01 16y agoI just had to do arithmetic. A 3 GHz processor would clock about 10.006671 cycles in the time it takes for light to travel 1 meter.
- GeoKangas 16y agoI don't think so. Light travels about 1 foot/nanosecond, so the travel time from monitor to eyeball is 1 or 2 nanoseconds, which might be 2 or 3 clock cycles. So I think at most 3 operations per CPU.
- yan 16y agoThere's 2 to 3 feet between me and my screen, my cpu has 2 cores, and modern CPUs can perform many simple arithmetic operations per clock cycle, per core. Not to mention what's happening in my GPU.
- pjscott 16y agoLet's take a concrete example. A Core-i7 980X Extreme Edition, the latest and greatest from Intel, can execute a maximum of four instructions in a clock cycle. (The numbers on actual code are probably a little over 1 instruction per cycle, which is really pretty good.) It runs at 3.33 GHz and has 6 cores. That's a theoretical maximum of about 43.336 = 79 instructions per nanosecond, on all cores combined. Assuming I didn't make some dumb arithmetic mistake. Of course, in real code you'll be lucky to get anywhere near that.
- acqq 16y agoRegarding double precision calculations (I can't compare random instructions) at the time OP mentions the PC FPU made something of the order of KFLOPS. Even assuming 100 KFLOPS (it was less), one current graphical card can be up to 5 million times faster than the PC of that time in some scientific calculations, that is, the gamer of today has under his desk the computing power of 5 million first PC computers. i7 can do 2 double precision adds per clock per core, that would give 36 GFLOPS on 6 cores (assuming 3 GHz clock), and at the same time ATI Radeon 5870 GPU can do 500 GFLOPS in double precision, that's 500 floating point calculations in one nanosecond. To cross the 0.5 meter distance the light takes around 1.6 ns, which means that during that time the CPU is able to do almost 60 FPU additions and the GPU around 800 FPU additions. Impressive.
- jacquesm 16y ago