Importance of Cache?

[chug4u]

If I upgrade to a P4 3.4Ghz  How important is the Cache memory  a 3.4Ghz  w/512 is $415 and w/2gigs is $1025.

[Soulyss]

I've kinda lost track of these things over the years so I don't know what qualifies as "enough" cache these days... but the first computer I bought was a P166 and it ALWAYS ran terrible, I had friends with slower CPU's but they ran games and such better than mine and I couldn't figure out why.  Finally I stumbled onto the fact that my computer had about half the cache that it should have had.  Since then I've become a big believer in having the biggest cache possible.  But that is coming from a position of paranoia and past experiences rather than any sort of technical knowledge on my part, ie I don't know what constitutes "enough" cache these days.  Back then you couldn't get any bigger than 512

[bloom25]

The impact of cache memory depends a lot on the applications you run.  Unfortunately it's not that simple, because in the case of the Athlon 64 and Pentium 4 the versions of these CPUs with different amounts of cache vary in other areas as well.

The Northwood Pentium 4 with 512kB of L2 cache is actually faster than the newer Prescott Pentium 4 with 1 MB of L2 cache.  (The Prescott had some other changes made that are designed to allow it to hit a higher clockspeed that negatively impacted performance significantly.  The Prescott also runs extremely hot.)  The version of the Pentium 4 with 2 MB of L3 cache is the extreme edition, which is otherwise the same as a Northwood.  This part is extremely expensive, but is the fastest of the Pentium 4s.

On the Athlon 64s, the 1 MB of L2 cache Socket 754 CPU have single channel memory controllers on die.  The new Socket 939 parts with only 512 kB of L2 cache have dual channel memory controllers on die.  The change to a dual channel memory controller typically more that makes up for the drop to 512 kB of cache.  (The new Socket 939 Athlon 64 FX CPUs have both dual channel memory controllers and 1 MB of L2 cache.)

[MOSQ]

Originally posted by chug4u
If I upgrade to a P4 3.4Ghz  How important is the Cache memory  a 3.4Ghz  w/512 is $415 and w/2gigs is $1025.

You would actually consider paying one thousand dollars for a cpu?

Why? So you can get frame rates in the 200's? Your eye can't perceive the difference in frame rates over about 60, and your monitor refresh rate is probably 85. Any frame rate over 85 gets displayed at 85.

[214thCavalier]

Well one answer comes to mind.
Turning up all the eye candy and still getting playable frame rates.

But $1000 is still a helluva lotta money.

[Siaf__csf]

Especially when the A64 can take him there with half the price.

[Overlag]

the P4EE would only be useful in a server area really, as it IS a server chip repackaged into a normal P4's socket.

as others have said, cache doesnt really mean too much....

P4 has 8kb L1 and 512kb L2

P4E (prescot) has 16kb L1 and 1mb L2, but its slightly slower due to longer pipeline. It also needs a monster heatsink to get rid of 103watts

XP Bartons have 128kb L1 and 512kb L2 upto about 2800 its faster than a P4, after that its slower.

A64 Socket 754, 128kb L1 and 1mb L2, single channel ram. Extra cache makes up for single channel ram, also gives it 200 extra rating. Ie the 1mb version @ 2000mhz is 3200 rating, the 512kb version @ 2000mhz is 3000 rating.

A64 Socket 939, 128kb L1 and 512kb L2, DUAL channel ram. Dual channel ram makes up for less cache (and cheaper for AMD to make)

anyway

512kb = ok
1mb = gooood
2mb = overkill