Simviation Forums

Can someone tell this twit what the buss is on a computer and it's role and importance?
It is driving me up the road!

Also what is cache?

Thanks

Ben

As far as I'm aware, a bus is a path for information.  Literally, a wire from one spot to another.  A cache is a temporary collection of files.

Do be advised, I'm not well read in nanotechnology, so take this with a grain of sodium chloride.

This is what was written by JBaymore in the thread Video Graphics for FS9.

So if your computer processor is not really high end, and your RAM is not a gigabyte in size and FAST, and the front side buss is not at least 800.... then don't be shooting at the really high end video cards yet.

I'm going to see what mine is (if I can find it) and hopefully someone can comment on it.

I'm not an expert on cache or bus architecture, but understanding these basic concepts should give you some idea of what goes on in your PC.

Cache:

A memory area where frequently accessed data can be stored for rapid access. In the case of CPU cache, it's an area of very fast ram that allows the cpu to perform it's calculations internally, without having to take a trip on the bus to access system memory.

Today, we are mainly concerned with CPU cache when we talk about performance. Cpu's contain different "levels" of cache ram (L1, L2...) and they perform different functions.

Below is a photo of an AMD Opteron CPU core showing the two areas of 64kb L1 cache near centre (white rectangles in blocks, one block of cache high and one low), and the 1 mb of

Definitions of Front Side Bus on the Web:

The main highway for data in a PC. It connects the processor, chip set, DRAM, and AGP socket. FSB is described in terms of its width in bits and its speed in MHz.
www.crucial.com/library/glossary.asp

The main path for data transfer in a computer, it connects all of the major components, such as the CPU, memory, chipset, and AGP socket. See Bus for more information on how the FSB operates.
www.upgradememory.com/Computer_Memory_G ... C15775.cfm

Front Side Bus (FSB) is the term used to describe the CPU data bus. This bus carries all information that passes from the CPU to other devices within the system such as RAM, PCI expansion cards, hard disks, etc.
en.wikipedia.org/wiki/Front_side_bus





In this pic, we see a modern board's physical copper tracks that carry the data on the bus, or the "wires" previously referred to by Scorpion. The physical "width" and size of these many tracks of copper demonstrate the complexity and shear size of modern buses.



There are other data buses, PCI bus, memory bus, AGP bus, etc.

Thanks for looking up that very informative description Congo. So how does my specs sound?

System bus:  2000/1600 MT/s

I couldn't find my system cache.

I didn't look it up, I wrote it.

Your bus spec tells me you have either a socket 939 or 940 based chipset. The reference to 2000/1600 mhz is generic and depends on the CPU / hypertransport frequency used (I think!). It's not indicative of your actual bus speed. However, the fact that you see the 2000/1600 specification means that your system is capable of those speeds, which is great.

If you would like a great program that's small, accurate and informative, try Everest Home Edition, it's a great tweaking aid, in the sense that it gives you real time system info.

http://www.lavalys.com/products/downloa ... =1&lang=en


Here, you can see my Front Side Bus properties, note that the speeds are not converted to DDR, but are "pure". Hence you see my FSB speed as 200 x 5 = 1000, this equates to the 2000 you see in your spec due to the 64bit hypertransport thingy and DDR.





Your system cache is your swap file or virtual memory, which is usually windows managed and is really just reserved space on your hard disk that programs use as virtual ram. You can set the swap file to be a constant size, (same min and max values) as a performance tweak, as long as your applications don't use more than the value you set. I have mine manually set to 1024mb.

Your Processor cache spec on the other hand, will be available in the cpu section of Everest.

My cache is L1: 64kb x 2 +  L2 512mb


When I look at your signature pic, I see immediately that the most meaningful info (your mainboard ID) is missing. The mainboard ID tells me what your system is capable of.

For instance, If I were to advertise my spec, it would read:

Asus A8N-SLI,

Now, here is the part I don't understand..........yet.....

This pic shows my FSB overclocked and the resultant PC bandwidth is up to over 7000mb'sec.

But look at my hypertransport speed, dropped to 600 odd, (presumably because the HT speed was auto-dropped from 5x to 3x by my BIOS because it couldn't handle the overclock and remain stable).

I manually set the HT to 4x and got the same bandwidth result.

So, I need to learn more about the peculiarities of the HT bus.

Thanks for your time Congo. Much appreciated. I'm a little wiser now.