Explain higher processor speed vs more RAM, please

[elfkin477]

After hearing "RAM makes your computer faster, so has as much as possible" so many times, I'm confused about new computers that I've seen ads for.

I know that computers can now have 1GB of RAM (if not more) now, so why do so many computers only come with 128mb? That's only 1/3rd of what I have in my three-year-old computer! Granted, I added 256MB after I got it, but they come with no more RAM than my baby did. (and I'm going to take out the 128mb block and replace it with a 256mb one I just bought)

So I've developed a theory...is this right?

If the CPU is of a significant size/speed, RAM isn't as important.

Which would be why a 2.7Ghz processor is paired with 128mb of RAM.

So would having 256MB of RAM or 512MB of RAM make a significant difference to a computer with that processor? Would a computer with that processor, which is a lot faster than mine (just over 700mhz) be faster despite having far less RAM? How does having a memory hog like XP (vs my current ME) or a onboard graphics card affect things? I don't know if there are computers that are 128MB RAM and still have graphics cards that share system RAM, but I suppose it's possible.

I'm trying to puzzle this out, because I want to know if it's worth the cost to upgrade the RAM to something higher than 128MB when I buy another computer at the end of the year.

[censored]

Someone will be along shortly to provide a more complete and technical explanation, I'm sure, but for the moment...

In short, your theory is wrong. A 2.7ghz coupled with 128mb will be incredibly handicapped, and you see computers sold with that configuration because 128mb is obviously cheaper than a more adequate amount - but it still allows the computer to be marketed as being "super fast," and the technically clueless will see the big number next to the ghz and think it's fast. This allows both higher profits and a lower price to consumers, thus making it a more attractive buy - to the technically clueless.

A non-technical way to think about it is that processor speed is how fast your computer computes, and RAM stores the data and programs you're currently working with. In practice, they work together for higher performance. Having too little of either will make it slower. 128mb is way too low; 256 is considered minimum for adequate performance. Get 512 if you're up for it, it's definitely worth it.

An onboard graphics card shouldn't impact Windows window-drawing performance but would make its presence known if you tried playing games, for instance. If that's not your thing, then don't worry about it.

[Nametag]

Originally Posted by elfkin477

After hearing "RAM makes your computer faster, so has as much as possible" so many times, I'm confused about new computers that I've seen ads for.

I know that computers can now have 1GB of RAM (if not more) now, so why do so many computers only come with 128mb? That's only 1/3rd of what I have in my three-year-old computer! Granted, I added 256MB after I got it, but they come with no more RAM than my baby did. (and I'm going to take out the 128mb block and replace it with a 256mb one I just bought)

So I've developed a theory...is this right?

If the CPU is of a significant size/speed, RAM isn't as important.

Which would be why a 2.7Ghz processor is paired with 128mb of RAM.

So would having 256MB of RAM or 512MB of RAM make a significant difference to a computer with that processor? Would a computer with that processor, which is a lot faster than mine (just over 700mhz) be faster despite having far less RAM? How does having a memory hog like XP (vs my current ME) or a onboard graphics card affect things? I don't know if there are computers that are 128MB RAM and still have graphics cards that share system RAM, but I suppose it's possible.

I'm trying to puzzle this out, because I want to know if it's worth the cost to upgrade the RAM to something higher than 128MB when I buy another computer at the end of the year.

RAM does NOT make a slow computer faster. Insufficient RAM, however, can make a fast computer slower. Yes, most base model computers are sold with the minimum RAM that will let it run at all. It's cheaper that way.

[5cents]

If your computer doesn't have enough RAM to store everything, then most operating systems (including Windows) will free up space in RAM by copying areas of RAM that haven't been used recently to the hard disk. This works fine, but there is a price - hard drives are about 1000 times slower than RAM.

Worst case is your computer is constantly moving RAM contents to/from the hard disk. This is known as thrashing. Turns your 2.7GHz computer into the equivalent of 2.7MHz.

If money is a problem, go for a slightly slower processor, and get (in order of importance) more memory, a faster hard drive (7200 RPM with 8MB cache at a minimum), and a real video card.

[elfkin477]

Originally Posted by censored

In short, your theory is wrong. A 2.7ghz coupled with 128mb will be incredibly handicapped, and you see computers sold with that configuration because 128mb is obviously cheaper than a more adequate amount - but it still allows the computer to be marketed as being "super fast," and the technically clueless will see the big number next to the ghz and think it's fast. This allows both higher profits and a lower price to consumers, thus making it a more attractive buy - to the technically clueless.

Ah. Given that the Apple and Dell comercials encourage people to be clueless ("why worry about giga-this and mega-that?") I can see how this tact would work. And here I was willing to give companies the benefit of the doubt...

[rjung]

Originally Posted by elfkin477

Ah. Given that the Apple and Dell comercials encourage people to be clueless ("why worry about giga-this and mega-that?") I can see how this tact would work.

Well, now you're getting into different processor families, such as Apple's RISC-based G4s and G5s vs. Dell's CISC-based Intel variants.

Short answer: if you're comparing two processors of different types (as in the example above), processor speed is (largely) meaningless -- a Mac with a 1 GHz G4 would spank a Dell with a 1 GHz Pentium, for instance. Unlike cars or engines or whatever else, there is no universal standard for measuring computer power; processor speeds will tell you how fast the processor churns, but the architecture of the processor will have a big effect on whether that churning is efficient or not.

And as others have mentioned above, memory affects computer speed only in the sense that not enough of it will slow down a computer -- once you've got enough RAM for a good-sized cache, adding more memory will only produce miniscule increases in speed.

For any computer on the market today (Macs or Wintel PCs), I'd recommend at least 256 MB of memory, though 512 MB and up is what I'd consider a "comfort zone." If you are considering a cross-platform switch (such as Windows to Macs), find a friend who's saavy with the "other" machine and pick their brains -- asking a Windows user about the virtues of a Mac (or vice-versa) is oftentimes as unproductive as asking Ann Coulter for suggestions on Democratic nominees.

[Toddly]

There are a lot things that affect the performance of your computer. The amount of RAM memory and RAM speed is key element in these factors as well as hard drive performance, video performance and CPU speed. A computer running 512 MB RAM vs. the same with 128 MB will definately have better performance. Each process that starts with your compuer uses a certain amount of RAM, each program you have running uses more, onboard video uses yet more. You can quickly use it all and then Windows uses Virtual Memory which is reserved space in the hard drive. This will drive down performance because RAM is many times faster.

[El Gui]

Originally Posted by 5cents

Worst case is your computer is constantly moving RAM contents to/from the hard disk. This is known as thrashing.

Isn't that what makes those grunting/grinding type noise (the noise that is also in sync with a light at the front of many computer cases)?

[Urban Ranger]

Originally Posted by censored

In short, your theory is wrong. A 2.7ghz coupled with 128mb will be incredibly handicapped

Not necessarily. It depends on a lot of factors. If the computer runs some sort of memory hog OS (e.g. Windows XP), yes. But what if it runs a small portable OS and the application is handcrafted in assembly?

[5cents]

Originally Posted by El Gui

Isn't that what makes those grunting/grinding type noise (the noise that is also in sync with a light at the front of many computer cases)?

That's the disk activity light. When it flashes, that means stuff is being read from/written to the hard disk(s). The noises you hear are the disk heads moving. Disk activity is normal and OK (you've got to load programs and save files somewhere, right?), but thrashing is when the disk activity is on more-or-less constantly for virtual memory load/save. If you are copying a 100 meg file, that's not thrashing.

[5cents]

Originally Posted by elfkin477

Ah. Given that the Apple and Dell comercials encourage people to be clueless ("why worry about giga-this and mega-that?") I can see how this tact would work. And here I was willing to give companies the benefit of the doubt...

It's just marketing. They used to sell on MHz. Now that MHz isn't such a big deal (who can tell the difference between 2.4GHz and 2.6GHz and 3.3GHz?), they sell on looks and image. As with anything else, you'll be better off if you ignore the marketing hype and buy what you need.

[Madness2MyMethod]

And if all that wasn't enough to confuse you, elfkin, the speed of the RAM should also be factored into the equation. And bus speeds....

[Critical1]

your proccessor is your computers I.Q.
Ram is How much stuff your computer can do with that I.Q. at one time.
not enough ram and you get Rainman...with enough you get Einstein.

at least thats one way to look at it.

if you plan on gaming at all you will want a bare minimum of 512 ram with 1024 prefered. a high end video card (G-Force4 or better) as well as a fast machine.

if you mostly surf and use things like word then 256 should get you by just fine.


if you really want to speed up your pc you need to clean up your start up folder. There is no reason for you to have Realplayer and Quicktime icons in the lower right corner of your pc 24/7 but something tells me you have both.

[Voyager]

It's even more complicated than the correct earlier posts say. Each computer has a memory hierarchy, of which the RAM is just a part. Processors come with several levels of cache, some on chip, some off chip. The closer you get to the CPU, the faster the memory is, and the more expensive it is to implement. Since you can never fit everything in the L1 cache (written L1$ often) on-chip, there is an L2 cache, often off-chip. where things get swapped to. Cache size, and the very complex logic to control them, is where all the hundreds of millions of transistors in the latest processors are going. There are usually separate caches for data and instructions. So, if you want to buy a fast processor, you need to look at cache size as well as frequency. The reason the old Celerons were cheaper and slower than Pentium 2's of the same frequency was because they had small or no on-chip caches. (I forget the details.)

When the data gets swapped out of cache, it goes to RAM (also when an explicit write is done.) In the same way, when you are running too many programs with too much data, you get swapped to virtual memory on disk. For each process there is a natural size of memory it requires to minimize swapping. If all of these added together exceed the size of your memory, you thrash. Say program 1 starts up, and finds it doesn't have enough memory. The OS swaps out program n. Then program 2 starts, and it doesn't have enough memory either. Program n+1 gets swapped out. Then program n gets a turn again, and swaps out program 1, and so on, and you hear your disk go nuts.

This is why more memory won't help if the stuff that you are running fits, but can really help if it doesn't. Newer programs and OS's assume more memory, and are memory hogs, which is why they don't work so well on old machines.

[Teelo]

I guess I might as well add the difference between 'DDR' and 'SDR'

Basically, Double Data Rate, and Single Data Rate. the idea is of course that DDR is twice as fast.

A friend of mines father told me that after some tests have been run, the DDR seems to only have about a 15% speed increase.
Sorry, no site. Just meer hearsay.

[5cents]

Originally Posted by Voyager

It's even more complicated than the correct earlier posts say. Each computer has a memory hierarchy, of which the RAM is just a part.

Hey, you forgot registers!

Originally Posted by Voyager

This is why more memory won't help if the stuff that you are running fits, but can really help if it doesn't. Newer programs and OS's assume more memory, and are memory hogs, which is why they don't work so well on old machines.

This is what counts. If the programs you run need (all together) 200MB, your system will be slow if you have 128MB RAM, fine if you have 256MB, and fine if you have 512MB. You won't really notice any difference between 256MB and 512MB in this instance (that is until you install the next version of your favorite programs, which want, say, 80MB RAM when before they "only" wanted 20MB).

As for all the cache stuff, it's true, and I have systems with a lot of cache (Pentium Pro, Pentium III, HP-PA, UltraSparc II, Ultrasparc IIIi) and some with very little (Celeron). For typical desktop use, if you compare two computers side-by-side, each with similar processors where the only difference is the amount of cache, the differences are not all that great. No cache is a bad thing, but a little cache or a lot of cache really don't make much difference in typical desktop systems.

Lots of cache can really help if you have a multiprocessor system.

[Voyager]

Originally Posted by 5cents

Hey, you forgot registers!

I wasn't expecting comp.arch! I've never heard registers considered as part of the memory hierarchy, since movement between registers and memory is under specific program control, unlike the case of cache, where the processor and/or OS does it for you. I'd say that disk you deliberately write to is not in the memory hierarchy the way disk used for virtual memory is.

<geezer> Does anyone learn how to program anymore, and, if they do, do they get some background in basic computer architecture? I'd think that you could code far more efficiently with at least a little bit of assembly language training so you'd know what is going on under the hood. Judging from the code I see, though, everyone assumes infinite speed and resources.
</geezer>

[5cents]

Originally Posted by Voyager

I wasn't expecting comp.arch! I've never heard registers considered as part of the memory hierarchy, since movement between registers and memory is under specific program control, unlike the case of cache, where the processor and/or OS does it for you. I'd say that disk you deliberately write to is not in the memory hierarchy the way disk used for virtual memory is.

I've never seen registers not considered part of the memory hierarchy. And your reasoning doesn't hold up, because you do directly address physical memory, and it is part of the hierarchy. Cite: http://en.wikipedia.org/wiki/Memory_hierarchy

Originally Posted by Voyager

<geezer> Does anyone learn how to program anymore, and, if they do, do they get some background in basic computer architecture? I'd think that you could code far more efficiently with at least a little bit of assembly language training so you'd know what is going on under the hood. Judging from the code I see, though, everyone assumes infinite speed and resources.
</geezer>

All the assembler programming in the world won't help you if your algorithms are inefficient. Assembly is (was? modern compilers are good, and modern processors are quite complex especially with scheduling) an option for little tweaks, but that's after you are sure you have made good choices for algorithms.