Kader have bought Sander Kan!

And is limited to 2G per process as far as I am aware, so I also had to upgrade to 64 bit XP at the same time the memory went in, to get around that limit.

MBQ

Haven't you used it to comupterise your model railway? What a waste of computer resources!

Only to control points to set a route so far - but that may be as far as go.

Cheers, Simon

Thanks, was fairy sure that was his name, but the middle initial is what couldnt remember. Definately a classic that just cos someone is top at one thing it doesnt necessarily mean he is an expert in something else.

Cheers, Simon

I dunno, but a dual core needs RAM in matching pairs, so 2x500MB, 2x1GB.

My layout is all DC - nothing digtal about it.

(I have run into kim elsewhere!)

Doesn't that depend on whether the motherboard supports dual-channel memory or not? My CPU is dual-core but the memory is only single channel.

(kim)

And I was talking processes, not processors!

MBQ

I dunno that either, but I bought 2x1GB chips compatible with my motherboard, and HP specifies matching pairs of RAM chips. Task Manager reports 3,144,104KB total RAM.

I have a matching pair of (1GB) memory boards but as they're only single channel there's no speed advantage.

(kim)

Correct

You're losing some speed, which won't matter unless you are into heavy gaming, or other heavy-duty graphics/video rendering. Word proc, etc is governed by your typing speed, which is slower than molasses in the freezer from your CPU's POV.

That includes onboard video RAM, I think.

HTH

It's pirate talk: "Avast there, ye landlubbers/trainlovers".

It has a separate video card with TV in/out.

Actually, 3GB is 3,145,728KB, so 1624KB is not available.

Sounds very curious. Doesnt include video ram at all. Are you looking at total physical memory ? plus is it vista or XP ?

Cheers, Simon

I'm looking at what's reported in Task Manager as Total Physical Memory. Help/About Windows gives the same figure. It's XP with SP3.

That would suggest there was already one GB installed when you added the other 2. But thats probably what you said. Dual channel possibly just means that one cpu can access memory without always blocking the other cpu's access. Of course they both need to be trying for an extensive amount of time for it to matter. Most other peoples systems I've looked at are crippled by lack of - or dynamically expanding - page space. Looked at a friends PC the other day - was running terribly slow but high CPU with task manager showing nothing using it - plus always accessing disk. Quick look showed although an additional 500mB ram installed the page space was set for only 500mB. Poor little system thrashing away swapping memory in and out.

Cheers, Simon

It is.

My system will use up to 100% memory, e.g. when converting AVI to MPG.

[...]

Dual channel RAM is not relevant to the CPU. Dual channel means only that the memory controller, which is outside the CPU, can access (== read or write) two chunks of memory at a time. This is an advantage when two different "threads" (processes of a single program) are requesting memory access. Memory access is considerably slower than CPU speed, so a CPU can switch between threads (and other processes) much faster than the memory controller can provide memory contents. So it can work one chunk of data while another chunk is being fetched. The net effect is higher CPU utilisation, which is what you want. If the CPU is waiting

50% of the time for memory access, its effective speed is only half of what it says on the box.

A dual core CPU in principle can run twice as many threads. In practice, the overhead of switching between threads and apportioning them to the two cores reduces this to about 1.5 to 1.9 times as many threads (depending on how well the program code has been optimised for dual core CPUs.) The latest dual (and quad) core CPUs from Intel include the memory controller on the chip itself, which should speed up memory access by a factor 2 to 5.

OTOH, most currently available programs, commercial or not, have not been rewritten to optimise threading, let alone optimise use of dual CPUs. This means that much of the time only one core is being used - you have in effect a single core machine. It's not easy to rewrite software to spread the work over two (or more) cores. That includes the OS itself. AFAIK, neither XP nor Vista are optimised to take advantage of the dual core CPUs available now, let alone the quad cores appearing in high-performance gaming machines. The games programmers get around this limitation by in effect loading a game-specific OS that usurps the machine. Also, Intel is putting more and more BIOS and OS functions into the CPU. This has been SOP from DOS days, and continues to be so because neither Windows nor Mac OSX include the special graphics routines needed for high-end games.

Cheers,

Dynamically expanding, or even fragmented, page files have little impact on performance in practice, for most users and most applications.

I assume you mean a fixed size, which just shows the danger of messing with settings without fully understanding the implications.

MBQ