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Thread ID: 49739	2004-09-29 02:31:00	RAM/Processor speed?	Thomasscelo (6211)	Press F1

Post ID	Timestamp	Content	User
276598	2004-09-29 02:31:00	Hello everyone, Sorry to ask such a basic question, but you see, I am not really a computer expert but still need performance from mine. I am running batches for my work (using Matlab for those who know) and I reached a point where one batch only can be processed overnight. And that goes on for several nights until I get some useable data. So I'm looking at increasing the RAM of my computer (with the basic idea that more RAM will make it faster). But I am limited to 512Mb of RAM in my computer that has a PIII 850MHz processor. My question is: if I go for a custom made CPU to replace my computer, is it better to go for a much faster processor or a much bigger RAM (assuming I can't go for both)? Many thanks, have a great day! Thomas	Thomasscelo (6211)
276599	2004-09-29 03:00:00	if your just crunching numbers then the faster processor is the wya to go, if you are multi tasking heavily then more ram is the way to go, however i would go for the faster processor as ram is far easier to upgrade than a processor	lagbort (5041)
276600	2004-09-29 03:06:00	Hi Lagbort, Thanks for your advice. I am actually "crunching number" as you say but this does involve a lot of memory as the process keeps recalling number already calculated which, I presume, are somewhere in the RAM. Basically, it is almost equivalent to a series of independent LOOPS that recall the results of the previous. Thanks ! Thomas	Thomasscelo (6211)
276601	2004-09-29 03:07:00	If you go to a new comp then you will be having to purchase new faster ram that will work in conjuction with the new comps cpu.	metla (154)
276602	2004-09-29 03:08:00	It depends. :D If you are processing huge datasets, memory is the thing to go for. If it's heavy iterative processing, probably CPU is the way to go. Anyway, the only thing better than lots of memory is even more memory. ;-) If you buy a computer now, you'd have difficulty getting a processor slower than 2GHz, anyway, so it's probably an academic question. You might be able to make a guess at what is your main problem by watching for continuous disk operation while the batch is running, which would indicate a shortage of memory. That is compensated for by swapping memory in and out to disk --- which is a severe hit on performance. But Microsoft do provide some monitoring utilities which will let you find out. You should find them in the Start/Applications/System Tools menu. If you monitor the CPU usage, and memory -- both real and swap -- you will find out the situation.. How much memory have you got at the moment? If money is limited, going to 512MB on the present machine might be the most economic option. The ideal would be to borrow some memory and see if it makes a substantial improvement. If you've only got 128MB or so, I'd say you need more, anyway. That's hardly enough for an MS operating system, let alone a mathematics package. ]:) I haven't used Matlab, but I would guess that it would like "reasonable" amounts of memory --- although it's been around for long enough for the coders to have worked with the constraint that memory has not always been as cheap as it is now. :D	Graham L (2)
276603	2004-09-29 03:10:00	Get yourself the fastest p4 you can afford and a Gig of ram,and a couple sata drives set up in a raid config..... Shouldnt cost you much.	metla (154)
276604	2004-09-29 03:19:00	Fastet. "P4" ?. Them ther be fightin words.	Jams (1051)
276605	2004-09-29 03:30:00	well,when it comes down to pure number crunching i would recomend either a p4 or an amd 64-bit 3500,the 3500 is just going to blow the budget so the p4 is the logical choice,for this sort of task it would (should) smoke a similarey(sp?) rated AMD.... 2.8gz p4 with a gig of ram would be the sweet spot.	metla (154)
276606	2004-09-29 03:30:00	Thanks for the advices. I'll get back to you guys once I've tried using a 256Mb RAM borrowed and a similar computer (384Mb) but with a faster processor than mine. I'll also check by changing my virtual address space available for Matlab. Regards and have a great day! Thomas	Thomasscelo (6211)
276607	2004-09-29 03:41:00	A quick look at Google shows that Matlab call for 128MB minumum, and recommend 256 --- a "user" (www . itc . virginia . edu) site recommends 256MB minumum, 512 preferred . One (heavy computational) application is said to run "well" on a processor faster than 500 MHz . "A couple of SATA drives" set up in RAID configuration won't help here . The "fastest P4" might give some improvement . A gigabyte might . Or not . After you don't need any more memory you don't need any more memory . By all means, if you have the "not very much", go ahead . But there might be cheaper approaches . ;-) My approach (after checking the memory usage) would be to have a look at the code . It looks as if you might be "compute-bound" . In particular, nested loops are notorious for "bad behaviour" . Just one variable recalculated unnecessarily in an inner loop can cost a huge amount of time .	Graham L (2)
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