Pentium 5? When and how will it be?

Mercutio

Fatwah on Western Digital
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Prof, if you'll go read the front page of arstechnica.com right away, you'll see that there's no talk of a Pentium5 until 2005, long enough for Pentium4s to hit 10GHz.
 

time

Storage? I am Storage!
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The idea of such a bandwidth-inefficient CPU at 10GHz makes me shudder. Presumably it will need dual channel PC4300 RDRAM or dual channel PC8500 QDR-SDRAM for optimal operation. 2133MHz octuple-pumped FSB, anyone?

RAM bandwidth hasn't kept pace with increasing CPU frequencies before, so I don't expect it to start now. :(
 

P5-133XL

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The whole point of cache is to compensate for the slow speed of ram. While time is correct that RAM speed has not improved at the rate of the CPU's, the RAM caching technologies have and that does a lot to keep the performance increasing rather than evening out like it would have a long time ago without it..
 

Handruin

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P5-133XL said:
The whole point of cache is to compensate for the slow speed of ram. While time is correct that RAM speed has not improved at the rate of the CPU's, the RAM caching technologies have and that does a lot to keep the performance increasing rather than evening out like it would have a long time ago without it..

If the ram isn't fast enough to keep pace with a 10GHz cpu, could the cycles be put to other uses?

Also, what about some type of distributed load over ram modules? Say, if the CPU is waiting "X" number of cycles for the ram, why couldn't a single ram chip be broken into segments so that when one segment is busy, another noe could be free for interaction? Almost like SMP ram (although I know ram doesn't process, but you get the idea)?

On a side not, have you guys seen the website for 10Gigabit ethernet? Talk about a speed of something that can't be utilized right now because of PCI bus speeds...they will have to create something like an "agp" port, but for NIC's.
 

Mercutio

Fatwah on Western Digital
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10Gbit ethenet is designed for trunk lines and aggregation points, Doug. It'll get to the desktop eventually (my guess is probably four or five years from now), but I don't think it'll be widely deployed, deskside, unless someone can get it to work over copper wire (coughNotBloodyLikelycough).
 

P5-133XL

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Yes to a limited extent CPU's do do stuff while it is waiting for ram: That is the part of the point of multiple pipelines and hyper-threading. However, in the end, the CPU is limited in how much it can do by the amount of data it can be fed. If that data comes from the cache then it will run fast, because the cache is fast and if it comes from RAM then the CPU will have to wait for the RAM.

With RAM distributed loading is called interleaving. It is more expensive for the MB manufactures to create interleaved RAM, so in modern machines you will only see that in server MB's like ServerWorks. That is the whole reason serverworks MB's can deliver the ram BW of 266DDR with 133SDRAM. You can tell a MB that uses interleaving when you need to populate RAM in sets greater than 1 at a time.

Part of the problem is that interleaving will increase bandwidth but does not help in latency. Think of the two as bandwidth= getting blocks of data and latency as the time it takes to get the first item. Somewhat akin to the difference in access speed and sequential transfer speed with hard drives. Interleaving helps, but is not enough when one really needs fater RAM.

Gigabit ethernet is not designed for a single machine exclusive use and thus the PCI bus limitation is not an issue. The point of gigabit or 10 Gigabit Ethernet is to have shared backbones for multiple users.
 

cas

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P5-133XL said:
Gigabit ethernet is not designed for a single machine exclusive use and thus the PCI bus limitation is not an issue. The point of gigabit or 10 Gigabit Ethernet is to have shared backbones for multiple users.
I disagree. 10Mb Ethernet was far more expensive than 1000base-T is now, when I supported Netware 2.x. With fully integrated MAC+PHYs @ $19 in sample quantities, the time of gigabit to the desktop is now.

My recent comments on 10Gb Ethernet can be found here.
 
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