L3 Cache?

[BitByBit]

It seems that only older motherboards, such as the Super Socket 7 boards for use with the old K6 support L3?
I suppose increases in memory performance reduce the need for L3, but memory-intensive applications would still benefit.
Can anyone shed any light on this?

 

[LTC8K6]

Well the intel P4EE's have 1MB of L3, and it doesn't help them all that much.

L3 on the mobo would be slower than the on die L3, so the effort is probably not worth it.

With the upcoming 2MB L2 P4's, L3 cache is going to look even less desirable.

 

[imported_Computer MAn]

Originally posted by: LTC8K6
Well the intel P4EE's have 1MB of L3, and it doesn't help them all that much.

L3 on the mobo would be slower than the on die L3, so the effort is probably not worth it.

With the upcoming 2MB L2 P4's, L3 cache is going to look even less desirable.

P4 EE's have 2mb of L3 last time I checked.

 

[NateSolberg]

With the Athlon 64's on-die memory controller, your system RAM is kinda like L3 nowdays. I was talking to my boss about this exact thing the other day. Why not put about 128mb of super-fast GDDR3 or something on the board and use it as a buffer to RAM? I think to be honest, it's just not worth the added latency/cost to figure out how to use it. The CPU's memory controller would have to somehow figure it all out, and it's probably just too much work.

On the Intel side, P-4 EE's with 2mb (yes Computer MAn) L3 really weren't all that impressive in my opinion. The architecture should really benifit from having a bunch of cache, as it has a giant pipeline that's really hard to keep full as it is. But I think we'll all agree, a properly cooled 3.8 P-4 with no L3 is faster than a 3.4EE with 2mb. It's just time to shuck that broken design and move on to Dual-Core P-M's for the desktop.

 

[VIAN]

If they chuck out the EEs, then they won't have expensive chips anymore.

 

[stevty2889]

The P4EE was hardly any kind of redsign anyway, until the Prescott EE's they were xeons in a P4 package.

 

[LTC8K6]

P4 EE's have 2mb of L3 last time I checked.

It still didn't help them that much.

It's just time to shuck that broken design and move on to Dual-Core P-M's for the desktop.

They aren't using your clock.

 

[Slaimus]

Super7 class computers did not have level3 cache. The stuff on the board is level2 cache. When it is used with select AMD chips such as the K6-2+ and K6-3+, which have on-chip level2 cache, then it acts as "level3" cache.

 

[stevty2889]

Cache on the motherboard was a lot slower than having the cache on-die on the CPU itself. Also, each level of cache is a bit slower with higher latency, so L3 cache is slower than L2, which is slower than L1.