E6300

I'm talking about weight loss, not overall health.

The only diet that works is caloric restriction. You can follow any fad diet you want, but if you don't expend more calories than you ingest you're not going to lose weight. Replace all the carbs in your equilibrium diet with the same amount of fat per mass and you're going to start gaining weight. It's as simple as that.

Well, fat certainly is worse than carbs, as far as weight loss is concerned. Fat contains twice the calories per gram compared to carbohydrates or protein, that's why things like cheese and oil are a big no-no if you're trying to lose weight. Butter is alright as long as you don't take a big ol' chomp out of a stick.

> When you start Firefox two times in a row, the dialog "Firefox is already running, please close the running instance" or something like this pops up.

On Windows, this only happens if the second instance starts with a specific command-line option (the name escapes me at the moment). Otherwise, the existing instance just opens a new window.

Only you need a volume license for that, and if you have the dough to spend on that, presumably you'd get a higher-specced CPU.

Yeah, since Windows Vista/7, when Documents and Settings was moved to Users, the system creates new user directories with a bunch of symbolic links/junctions that don't seem to be properly created and always cause issues when copying the directory to another place or deleting the directory. I always get this problem when moving my profile directory out of the system partition.

Incidentally, it's amazing that Windows still doesn't let you specify a custom location to create the profile directory of a new user.

You are again conflating high bandwidth and low latency.

> So to not be memory bound you need to run an extra 15 times more instructions... without adding any cache misses, just to execute one instruction per cycle (a fraction of the possible). If it's less you are memory bound.

Yes, if you do operations in a lineal access pattern like this the performance will be bound by the bandwidth. This is the situation I was referring to above.

> Now imagine it's not perfectly sequential, and instead you have to retrieve something from memory before you know where to go next. Like say a database index, binary tree, or linked list. Instead of getting 8 bytes @ 2400 Mhz you get 8 bytes per 70 ns. Keep in mind that's 8 bytes per 1/2.4 ns vs 70 or 168 times worse.

> Suddenly instead of needing 15 times more instructions you need 2500 instructions per memory load, all without a extra cache miss.

> So as you can see it can be quite easy to be memory limited.

No, in this case you will not be limited by the bandwidth, but by the latency. Having more bandwidth will do nothing, because at 8 bytes per 70 ns you're only moving about 109 MiB/s. If 100% of the memory accesses are cache misses (they won't be) and the application uses all cores then yes, doubling the number of memory channels will double the multi-thread performance (unless channel count = core count), although the single-threaded performance will stay unchanged. Additionally, in this particular load you could get away with relatively low frequency RAM, which won't significantly affect the latency but will lower the total bandwidth (it will still be way higher than 109 MiB/s) and will be cheaper.

An application being cache-unfriendly doesn't imply that it will be bandwidth-bound. If the application reads single words from random locations it will be cache-unfriendly and latency-bound. If it reads 1K contiguous bytes from random locations it will be cache-unfriendly and possibly bandwidth-bound. If it scans the entire memory space sufficiently quickly it may be both cache-friendly and still bandwidth-bound.

I can't speak for the server market, but I'm certain that the high-end desktop market is composed primarily of people who do run top-of-the-line specs just for fun.

For all the cases you mention, the critical factor is the product of the average transaction size and the transaction count per second. As long as this value is smaller than the RAM bandwidth, the application will not be RAM bandwidth-bound.

Generally speaking, databases are kept in memory to minimize latency, not maximize throughput. Bandwidth is not really a problem. Having to update 10 GB/s of a database would be highly unusual. Having to get data from random positions in a disk or SSD is much more common.

As for the message broken, it's not clear to me why the bandwidth would "of course" be the limiting factor.

The only situation where I imagine that could happen is if you need to apply a small number of instructions to a massive data set that's fully loaded in memory. What sort of application are you running? If you can say, obviously.

> A quad channel system will have twice the throughput of a 2 channel because there can be twice as many cache misses being handled at once.

Sure, that's the theory, but in practice it doesn't seem to make much of a difference, at least not for dual vs. single.

Are there any applications that are RAM bandwidth-bound, though? The main bottleneck is supposed to be RAM latency.

Going from single channel to dual channel offers like an 8% performance increase, IIRC. Is there any reason to expect any different with quad channel RAM?

VT-x and VT-d are definitely not on AMD. AMD has its own versions of these sets that do basically the same, though, and AFAIK all hypervisors support both.

> difference between fiction and non-fiction

Wait, was that actually part of a curriculum? Surely if you know what "fiction" and "non-" mean you can understand the difference between the two.

I know I'm gonna get downvoted for saying this, but this is kinda dumb. Might as well look for Dyson spheres by looking for gravitational lensing around dark spots in the sky.