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Changing L2 Cache Size...

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by cyberghost_1

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Hello again... I'm using a Compaq Mini Netbook CQ10-120LA...Win7 Ultimate x86, Atom N270 @ 1.60GHz, 160GB SATA-II HDD and now 2GB DDR2-800 PC2-6400 RAM. My Q is: What are the effects of changing my L2 Cache from 256k to 512k?? The thing is that CPU-Z (CPUID) and Everest Ultimate tell me that my L2 Cache is 512k...BUT Windows 7 Manager tells me that its actually at 256k... Truthfully I'm confused... What's better as far as performance is concerned?? 256k or 512k?? I honestly don't know much about what the L2 Cache does and its purpose... Please help me out guys I would really appreciate any and all info concerning this... THX...

19 replies

by oh smeg

Than I attempted so here's my reward to you.

:-bd

:-bd

:-bd

:-bd

Col

by ansugisalas

Yay :D
Did ya mean the Wikipedia link, or the "You may not need to know" ;)

by cyberghost_1

I have a program called Windows 7 Manager that lets me me tweak/modify/optimize/clean Win7... Under the Optimizer section >System Speed >Increase the Performance of your CPU (Second Level Cache) there are options i can select from to set the L2 Cache... ranging from 256k up to 16mb. There is an option that says "Query" and it gives me the actual L2 Cache size... at first it said 256k, then i selected the option to change it to 512k... The thing is that Everest Ultimate and CPU-Z show me that I had 512k to begin with... i know that my Atom N270 is Single Core with 2 Threads and it is in HT mode...

by oh smeg

So it is using both Threads and splitting the L2 Cache equally between then as it should hence the Windows Manager showing you 256 K of L2.

While you can alter this under the software that you have as much as you like all it is going to achieve is to set aside more of the HDD space and Virtual RAM commonly called your Page File or Swap File and make them mimic the CPU's L2. It may help with performance but it may also make things worse attempting to confuse the system into performing out of specification.

You can give it a try but you need to understand that the CPU has 512 K split between the 2 Threads it is running. ;)

Col

by oh smeg

That is written to in an attempt to speed up actions. This can be in the CPU for instance and acts to give a constant uninterrupted stream of Data for CPU intensive processes.

Buy just the same it can also be referring to the Cache on a HDD which does the same thing but in the case of the CPU it tries to minimize Read Write Operations Lags from the HDD.

Here though I would think that this is referring to the CPU which supports Hyper Threading so it accepts 2 Streams of Data and has 256K of L2 Cache per Data Stream hence the 2 X 256 = 512.

You can not change this figure as it is part of the CPU and is to do with the way that the CPU works.

As you have been told previously these Netbooks where never designed to run a OS as intensive as 7 and the hardware is not up to the job that you are giving it.

Max out the amount of RAM it is possible to install and that is about the best that things will ever get here. ;)

Col

by seanferd

The cache is split between two cores, since HT makes one core "look like" two.

XP did, however, like to short you L2 cache, which was fixable wit a registry edit.

by cyberghost_1

What might be the consequences of altering the L2 Cache with the software to 512k...I'm assuming that my system will be using 512k for each thread instead of splitting it in 2 and like u mentioned 256k per thread... I realize that my Netbook isn't designed for Win7 Ultimate and neither is the Atom N270 @ 1.60GHz...but I have upgraded to 2GB DDR2-800 RAM Memory and I have noticed a considerable increase in performance... I can't really notice any further increase when I set the L2 Cache to 512k... at least not yet. Does the L2 Cache have anything to do with running large programs?? Like Photoshop, CorelDraw, AutoCAD or any other Memory hoggers?? Might I notice the increase in performance there??

by seanferd

It is a processor instruction cache, not a code/data cache like system RAM.

Any improvement would be in the speed of your more processor-intensive applications. Try running a processor-intensive operation on an image in PShop with and without the setting modified, and time these.

Negative consequences could be just about anything.

by ansugisalas

It will be using 256 for each thread (unless your program tells the BIOS not to allow HT, somehow... which is unlikely - unless the process contains a very scary period of "DO NOT TURN OFF YOUR COMPUTER WHILE SETTINGS ARE CHANGED" or something to that effect).
There will likely be a couple of 256 HDD caches set aside for "CPU L2 emulation", with instructions for it's use... somehow.
It's never going to be the same as CPU L2, no chance.
It's just some furry setting in a "performance optimization app" which are usually of limited usefulness anyway.
The only way to see if it does more good than harm (I'd say that's about a 50/50 at best) is to benchmark it with and without it.

It's going to take some processing power to use the HDD in that way, and it will put some read/write lag into the process, so I think it's not going to help at all, but you go and benchmark it, then you can educate us on it! ;)

by santeewelding

[i]Wrongly[/i].

Otherwise, you carom off into where angels fear to tread, not to mention epistemologists.

Even, were you to have said it the way I suggest, you got one tough row to hoe.

by cyberghost_1

What Benchmark software would u recommend?? I have Everest Ultimate... would that be sufficient?? Or is there better SW out there?? I benchmarked using Everest and my results were about the same but I still performed less than an Atom 230 HT with the same Chipset and RAM clock speeds.. but only on 4 of the 6 tests I performed...any tips...

by ansugisalas

out of quack, I see.
How about "What you assume is wrong?"
Should have stuck with "Read more, think less", I guess.

by santeewelding

After, "about". Inadequate though, still.

Bone up on things like, Algorithm of the Almighty.

Hastens to add: crumpets and jelly, too.

by ansugisalas

progressed into operators.
Turns out, the thing has to be implemented at every level, by hand... shouldn't take but a couple of millennia.
It's ping pong.

by santeewelding

You realize, have nothing whatsoever to do with a tech site.

It's all automated. All, automatons. Unwelcome interlopers, we are.

by ansugisalas

We utilize the vessels proffered to us, by happenstance, and by mollusks of all sizes.

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