how does the cache memory affects the system..?

Question

i heard that size of the cache mem increases the speed of the sys but amd sys eventhough has less cache mem compared to intel is claimed to have better speed... how is this possible?

Answer 1

The architecture (the way the instructions are actually executed) are completely different in the two chip series. AMD processors are faster for many types of programs than the corresponding Intel chips. Cache is only one piece of the puzzle.

Answer 2

You are comparing apples to oranges.

To look at the benefit of cache (specifically L2 cache), you need to compare two similar CPU models from the same manufacturer. When you do that, the benefits of having more cache are quite clear.

Furthermore, you are only taking into account the Pentium 4 and Pentium D CPUs in your question. You should read about Intel's newest line of CPUs, the Core 2 Duo. This desktop CPU is the next generation offering from Intel that is currently winning the speed war, packing more punch than AMD per MHz. For example, a 2.4GHz Core 2 Duo crushes a 2.4GHz Athlon 64 FX by as much as 20% in many benchmarks and 15% across the board. That's simply amazing. It even does so at lower temperatures and by consuming less power.

You can read more about it here:
http://www.tomshardware.com/2006/07/14/core2_duo_knocks_out_athlon_64/


AMD's answer early next year will be a new CPU codenamed "K8L". It will be the next generation of the current Athlon and likely compete well with Intel's Conroe, at least that's the prediction based on the paper specs. However, it's quite clear that Intel beat AMD to the punch and could likely have positioned itself back at the top for the next year or so. Who knows, though. AMD and Intel have been playing leapfrog ever since CPU's hit 1GHz.

Answer 3

The cache is a high speed memory where the CPU exchange its datas with the rest of the system. The standard memory (RAM) is slower than the cache, so if the CPU needs some info from the memory, it first needs to copy that info from the memory (slow) to the cache (faster) where the CPU can access it then after copy it back into the main memory.

There are two (sometimes 3) levels of cache memories, the level 1 is very fast (usually as fast as the CPU, but not very big) then the level 2 (bigger, slower but still faster than the main memory).

The more cache you have the better it is. However, there is some limitation to that: if the info need to be moved back and forth from the main memory, you lose the advantage to have a cache as the limitation will be the speed of the main memory

The size of the cache is not really a good element of comparison of the speed of a system.

Answer 4

Cache does make a difference in performance. For instance, the two cpu's you mention, the Athlon 64 and the Pentium 4/D, the Athlon has 4 times as much level one cache (the most important of all cache) as the Pentiums. It's not the only reason that the Athlon 64 is faster, but it's definitely part of it.

And the guy above me is correct. The Core 2 Duo's are ~20% clock-for-clock (at the same speed) as the Athlon 64's are. They're almost impossible to find yet, though, and they are being sold for outrageous prices, because of the low supply.