3 ms·
CPUs are fast but the ratio of latency of random access vs. maximum bandwidth is getting worse. In nanoseconds, approximately: 10^7 Disk seek 10^4 2KB ove
by alecco 16y ago
CPUs are fast but the ratio of latency of random access vs. maximum bandwidth is getting worse.
In nanoseconds, approximately:
10^7 Disk seek
10^4 2KB over 1Gbps
10^2 RAM uncached reference
10^1 L2/L3 cache reference
10^0 L1 cache reference
That's why systems don't feel fast lately. In particular for big data or bloated software that can't fit well within the caches or shared systems doing a lot of frequent switches (VMs in particular.)
Many classic assumptions for algorithms are outdated. Like avoiding full sequential scans. Those are fast for simple operations.
- jjcm 16y agoSSD's have become viable in terms of $/GB to justify them in a server room these days. I'd highly recommend moving to them (for your boot drive/VMs at least). It will make a world of difference. $400 may seem like a lot to spend for 160GB of storage, but knocking off two orders of magnitude off your seek time quickly becomes worth it when you're running four VMs off it at once.
- alecco 16y agoSeagate Momentus XT hybrid is very cool. Probably the best bang for the buck at the moment. http://www.anandtech.com/show/3734/seagates-momentus-xt-review-finally-a-good-hybrid-hdd/ http://www.anandtech.com/show/3734/seagates-momentus-xt-revi...
- thelabyrinth 16y agoIf you haven't read a lot about SSDs, you should read the big Anandtech article: http://www.anandtech.com/show/2738 http://www.anandtech.com/show/2738 . I didn't think SSDs were that important until I read this and was like, "Oh, I should get one." Which I haven't done yet -- soon, though. When AppleCare on my iMac expires.
- alecco 16y agoSSD (80GB, Intel) + hybrid (500GB, Seagate)