2MB Cache Vs. 4MB Cache

Hey, I'm sorry if this question sounds really stupid or if its been answered before. I know its been touched on in the forums already but I swear I've combed them trying to find an answer and tried google searching it and am still really confused.

What exactly is the difference between a 2MB cache and a 4MB cache? I am currently buying a T60 laptop and the only two processor options offered are a T5500 and T7200. Upgrading to the T7200 results in nearly a $150 price increase which is kind of steep for me.

I'm not really concerned about the speed of either processor. I see that everyone is in agreement that there is only a modest speed increase at best for most applications. The divisons on either processor just stem from the the idea on whether or not this speed increase is worth it (which is of course, oppinion). What I AM concerned about though is whether both are 64-bit processors or not. I've seen some people say that the 4MB cache is what makes it 64-bit and other people say that just having a Core 2 Duo in general is 64-bit. These are two totally contradictory statements and I am wondering if anyone would be able to help me.

Plus, I notice on the intel site that only the T5500 Cored 2 Duo lacks the ability to have "Intel Virtualization Technology". What the heck is that? Would I need that?

Thank you for all of your help.

 

No idea on the Virtualization, but Core 2 Duo is 64-bit, period. The t5500 and t5600 are both 64-bit even though they have the 2mb cache.

By the way, it is in NO way worth the upgrade for a whopping $150. I personally wouldn't spend any more than $50 on that upgrade, or I wouldn't get it.

 

Both are 64-bit as stevenator128 said.

The difference between cache sizes is that the more cache you have, the faster math and other things can be done. Cache stores the most frequently used instructions to save time. In everyday work, there will be no noticeable difference. If you are doing a lot of number crunching, the extra cache might come into play.

If you don't know what virtualization is, don't worry about it as it will not affect you.

 

Core Duo vs. Core 2 Duo

 

Cache size has nothing to do with features. It's just how big a buffer it has on the chip to cache data, so it doesn't have to wait for the RAM to catch up. So more cache provides a modest performance boost, and nothing else.

 

If the $150 is a lot to spend on an upgrade, I assure you that you'll be fine the the T5500. It's a very powerful CPU. Chances are you wouldn't notice the difference or even need the extra processing power anyway.

 

Thank you for all of your help everyone. I really appreciate you all clearing up what a 2MB cache and a 4MB cache are and what constitutes a 64-bit processor.

But no one can tell me what "Intel Virtualization Technology" is? I don't like the answer that if I don't know what it is, I shouldn't worry about it. After all, there are lots of things that I don't know; but just because I don't know them doesn't mean they aren't useful or important.

 

It is basically hardware support for people who want to run 2 operating systems virtually using software such as vmware or Virtual PC without the need to partition or dual boot the hard drive. It helps out people who want to test new OS/applications without having to go through all the trouble. It is mostly aimed at Professionals & business users, for the home user it is of little use unless you want to try out different OS virtually.

 

It's true, if you don't know what it is, you shouldn't worry about it.

As said above, it allows you to run multiple OS'es simultaneously, without having to fall back to software emulation.

 

How much % benefit does it provide if running VMware? Can only one O/S be virtual? If trying out Multiple GNU/Linux bundles w/ M$ XP pro (dual or #x Boot), would it better 2 have the Windoz O/S virtual?

Would IVT provide any benefit when rendering in Digital Video editing?? Adobe Premiere or Final Cut PRO.
Appears a larger cache 4MB would make a big difference to render DVE.

 

It only allows you to run multiple operating systems *simultaneously* on the same system. Nothing else. It does not speed up video encoding, brew coffee for you, increase your frame rate in Quake 4, download pr0n or overclock your system.

That's the benefit it gives. No more, no less.
Most people only need one OS. Those who want more than one tend to just use dualbooting to run the one they need when they need it, because they only need one at a time.

Hardware virtualization only becomes useful when you specifically need to run multiple OS'es at the same time. Like, if you're developing your own OS, you can run it on your system without having to reboot. Or if you're running a bunch of servers, they can be put on separate virtual machines, so that if one crashes, the others aren't affected.

And that's it.

And at the moment, even that isn't exactly straightforward. Most available solutions still run like VMWare, basically letting you run an OS in a window inside your "main" OS. That's pretty slow, even with VT support.

It only really gets interesting when hypervisor software becomes widely available, allowing you to run multiple OS'es in parallel, without having one "hosting" the other.

 

Thank you for all of your help everyone. I really appreciate it.

 

Just a small update. Although laptops are coming out with Intel VT technology, some laptop vendors disable it in the BIOS so that you can't enable it. So in some cases, you're purchasing a laptop with Intel VT technology but don't get to use it. If you do plan on using it to run Xen, for example, then double-check with the laptop vendor to make sure that Intel VT isn't disabled. CPUs with AMD-V (AMD's version of VT with a few enhancments) don't allow you to disable it, so it's in the laptop and the laptop vendor can't do anything about it. It's included by default in all Turion X2 processors.

 

I would say: if you are going to configure your notebook with 2 GB of fast (667 MHz) DDR2 then go for the 4 MB L2-cache. Like stated, L2-cache supports the connection between CPU and RAM. So if you have fast RAM and low L2-cache, the L2-cache will become the bottleneck.

Charlie

 

Not really. The cache bandwidth is the same, regardless of cache size. The difference is that with a smaller cache, data more often has to be retrieved from / read to RAM, which takes longer. It's not so much a "bottleneck" (which implies that it is limiting total system performance, so that other improvements won't matter), it's just another factor affecting overall performance. More cache is faster, just like higher clock speed is faster.