This is why a lot of programs display buffer length in units of time, since those are constant across different sound formats.

Just a few things I’d like to add; Patrick here seems to mostly know his stuff, but there’s a few extra points of interest I’d like to comment on:

1. By the numbers and my understanding of DDR and DDR2 operation, latencies are only equivalent between the two if the timings are double between the DDR1 and DDR2 sticks. For example, a DDR-400 stick running at 2-2-2-5 would be, in theory, equivalent to a DDR2-800 stick running at 4-4-4-10 timings. The same DDR stick running instead at 3-3-3-8 would be equivalent in latency to a DDR2-800 stick at 6-6-6-16 timings. The bandwidth, obviously, would also double when going to DDR2. In truth, this is never quite true, and in general DDR1 systems appear to have a larger latency lead due to the fact that the majority of DDR1 systems in circulation are AMD S939 with an integrated dual-channel memory controller, instead of an intel based system on LGA775 which will have an FSB-based memory system (which is inherently higher latency).

About the question relating to memory usage percentages and when it’s time to upgrade – yes, it is in theory true that you’re fine until you hit 100% memory usage, but there’s a bit of a caveat. A number of programs examine how much memory the system has and will, for performance reasons, try and tailor their usage to stay within the physical system ram. In this way, they’re not dependent on the operating system’s pagefile system and have more control over what is swapped in and out of ram from the hard drive (the program is what knows best about what it’s likely to need next in terms of swapping). As such, you will often notice that if you were close to your maximum memory running a game/application and then double your memory, the same program will consume more memory. It’s not that it’s suddenly being wasteful – it’s just that before it was cutting back its own usage to stay within the system’s limits, and can now reserve a larger chunk of memory to operate as intended. The end result of this is that you can often see performance increases from boosting your ram even if you aren’t normally quite hitting 100% as it is right now.

Kyle also asked a question about if it’s possible to determine if a chip has been overclocked after the fact for warranty reasons (to my knowledge, not easily) and if boosting his voltage and dropping his RAS delay from 16 to 12 will net him a performance improvement – which it will, but RAS actually has only a very minor impact on overall memory performance, so it’s probably not worth the trouble.

The only other thing I’d like to add is that Patrick mentioned that a system is only CAS3 if it’s 3-3-3-8 (any slower on the 2nd, 3rd and 4th timings and it isn’t CAS3). This is not strictly true – each of those 4 timings has a different name, in normal order of appearance: CAS-tRCD-tRP-tRAS

These names mean:
Column Access Strobe
RAS-to-CAS Delay
Row Precharge Time
minimum Row Access Strobe

So, if the first number is set to 3, then the CAS is actually 3 regardless of what the other numbers are. This is a question of convention however, because when a ram stick is called “CAS3″ it generally refers to the JEDEC-specified arrangement of timings where the first value is 3, so in this case JEDEC’s CAS3 standard is 3-3-3-8 and CAS4 is 4-4-4-12 (CAS5 is 5-5-5-15). In short, the JEDEC standards specify a full 4-set of timings for each possible CAS value, but other combinations are possible and still technically speaking called CAS3 or CAS4 etc… as their CAS value is set to that – but in most cases these other combinations include slower values for the 2nd, 3rd and 4th timings than the JEDEC spec, and will thus not perform as fast as JEDEC-standard CAS3.

PS: I know I said that was my last point, but there’s one more quick thing I forgot to mention – all the confusion about memories and timings and why this isn’t automatic when it should be centers around one simple fact – the standard voltage for a particular memory type used to always be the same regardless of speed or grade, so the SPD chips responsible for autosetting the timings don’t have a field in them for the required voltage for the listed timings. As such, if your stick is spec’ed to run at 4-3-4-12 timings at 2.0v (higher than the DDR2-standard 1.8v) then your motherboard doesn’t know what to do because all it has in its SPD chip is timings for the standard 1.8V voltage. This problem will, eventually, be rectified in later SPD chips, and in some special cases (nvidia’s EPP for example) is already implemented.

Would 15 seconds be long enough for my cpu to damage itself? I have a heatsink on it too.

Hell, even the power button on your case has no power flowing through it, its a simple event trigger, the motherboard is already on: it just switches everything else on when you press the button.