4 ms·
I remember when 24 MB was a respectable size for a hard drive. Now we've got CPU caches that big. It's downright ridiculous.
by sketerpot 17y ago
I remember when 24 MB was a respectable size for a hard drive. Now we've got CPU caches that big. It's downright ridiculous.
- Andys 17y agoCPU caches will soon be big enough, and flash fast enough, that there won't be any system RAM anymore. Your programs will basically run directly out of flash, and made performant thanks to huge CPU cache.
- djcapelis 17y agoThat's just not going to end up true for a general system. For some embedded systems that's a possibility, but the type of write wear system RAM gets is very different than the type of write wear hard drives get. A few people had visions of this, but any engineer who's run the numbers and looked at the trends in flash technology knows it's extremely unlikely that flash will replace RAM before it eats dust because of minimum theoretical densities. STTRAM[1] might be capable of this when it comes online and in production, but it seems flash is unlikely to reach this point and STTRAM is still in development. [1] http://en.wikipedia.org/wiki/Spin_torque_transfer http://en.wikipedia.org/wiki/Spin_torque_transfer
- djcapelis 17y agoFor comparison: POWER6 is 32mb. Large caches are becoming one of the largest performance wins on processors as I/O bottlenecks become more severe. By all good estimates it's only maybe 4-10 years before we have to worry about straight up running out of pins on the chips. (We can put more cores in 'em, but we actually will have a really hard time scaling down the pins that connect the die to the rest of the computer, so this will be another I/O bottleneck. The die is going to need as much cache as we can give it.)