Memory Performance in Chipsets

[JamesAW]

Hi,

I am curious - I have read how Intel has advocated the use of RIMM's to achieve the full potential of CPU's with exceedingly high clock speeds. I understand the disadvantages of RIMM's namely high cost. The question I have is if this is true, why do the majority of chipsets and motherboards particularly Intel's own Server Chipsets still use none-RIMM memory. I understand that this other memory format leads to cheaper systems, but for those that do want to buy a PC with ultimate performance (2.5GHz and beyond), what is the point in manufacturing chipsets with inferior memory. Do they use some technological trick to achieve similar or better performance, or are these motherboards simply bottlenecked by the memory. How can those server motherboards using for example 2 or more 2.6GHz Xeon CPU's ever hope to run at their peak with DDR266 memory.

I also would like to know why recent reviews of Intel CPU's have not included reviews of performance with Hyperthreading switched on.

I am hoping to build my next generation PC using an Intel P4 @ 3.06GHz but am tied between the Intel 850E chipset with superier memory and the Sis 648 chipset with improved features but with up to DDR400 memory which I understand is not quite as good. I am not even sure if these chipsets are appropriate to take advantage of Hyperthreading.

The PC I finally build will be the last in this generation, the next one I expect will happen later after the forthcoming technological leaps e.g. Serial ATA, PCI Express etc have occured over the next year or two.

Anyway I would be grateful if I could find some information on this.

Thanks

A little routing around and I have found out that SIS has produced the SIS658 using the same SouthBridge as the 648, which seems to be a suitable alternative to both the I850E and SIS648.

Unfortunately motherboards based on this chipset are not yet apparently available. That is unless Tom is sitting on some waiting for NDA's to expire.

Has anyone had problems with SIS Chipset that might give me a reason not to use a MB based on this chipset?

JW

<P ID="edit"><FONT SIZE=-1><EM>Edited by JamesAW on 09/19/02 02:26 PM.</EM></FONT></P>

 

[Crashman]

Well, the majority of Intel's high end chipset used RIMMs for a couple years. But now they have dual channel DDR chipsets for the P5 XEON, these being server chipsets and lacking some of the features wanted in a desktop chipset, while providing other features that are not needed. Intel simply hasn't introduced a Dual Channel DDR Desktop chipset because 1) The extra traces on the boards would raise cost by as much as $3 a board, 2)Intel makes boards, they want to keep as many of those $3 as they can without raising prices 3) $3 in manufacturing cost means at least $12 at retail level, the majority of customers being cheap 4) Intel would have to design a new chipset and manufacture it, costing them millions 5)People are too stupid to mount memory in pairs, which would result in a lot of non-defective boards being returned as defective. While the customer is responsible for stuff like this, processing all that stuff cost money.

SiS of course realizes that there are enough performance customers to warrent the production of such as chipset on a smaller scale, which is OK because they are a smaller company. But they have yet to release the 655, and only have 2 weeks left to remain on schedule. Their single channel chipsets are quite good, outperforming other DDR P4 chipsets, and having no known problems. But even these lag behind the performance of the i850E with PC1066.

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[JamesAW]

I have done a little more research, having read articles on Intel and RIMM's and have learned that there is little future in investing in the Intel 850E chipset inspite of it's advanced performance. A server chipset would be impractical and too expensive for me - I want a good machine but I don't want and cannot afford the costly hardware. SIS on the otherhand appear to be embracing RIMM memory so if I need to upgrade or replace my motherboard I would likely be able to reuse the components on another similar SIS Chipset.

I'm going to bide my time for a little longer and wait to see what emerges from SIS and the various motherboard manufacturers over the next month or so. I quite like the idea of the SIS658 Chipset so unless something better emerges elsewhere then I can hang around until then - The processor I want is not due to be released until November anyway.

In any case it is likely that I'll be away from home training in holland during October so I will hopefully be able to start building the system when I get back.

Thanks for your information and advice

James

 

[tombance]

Im just interested, what was the performance of the Pentium 3 with RDRAM, i mean the i820 used RDRAM and supported p3 right?

My sig's faster than yours, and it overclocks better too....

 

[Guest]

i820 based systems pretty well sucked, but i840 based systems were about the best there was at the time. That is if you could afford everything it took to build one. Back then RDRAM cost a small fortune, and the i840 needed to have pairs of the modules installed.

 

[Crashman]

i840 needed pairs? Why? i820 used single modules. I'm going to have to see proof for that, and I mean from a motherboard manufacturer.

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[Crashman]

WTF are you talking about? You see no future in the i850 why, because of RDRAM? But yet you'd purchase an SiS board that uses RDRAM, because you might be able to use the RDRAM on your next board? You speak nonsense, Intel chipsets use the same RDRAM as the SiS 658. And if you're looking at future compatability with your parts on newer motherboards, guess what, your chipset is part of the motherboard, so it gets replaced whenever you replace your motherboard.

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[Crashman]

Wait a minute, I forgot to ask, why was it you liked the SiS 658 over the 1850E?

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[Crashman]

i820 was a little slower than the VIA whatever you called it, which was a little more slower than the i815, which was a little slower than the BX. The i815 was purposely handicapped by a few percent to prevent it from making the more expensive i820 look bad, but it still made the i820 look bad.

You have to remember that SDRAM has low bandwidth and low latency, RDAM has high bandwidth and high latency. The PIII only had an SDR CPU bus, so it didn't need the extra bandwidth. But the lower latency of SDRAM made it the clear winner.

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[Guest]

i840 was dual channel and required 2 modules. Look at this old article here:

http://www.tomshardware.com/mainboard/99q4/991215/index.html

I really wanted this setup, but back then could not even justify the cost of the RAM required. I'm surprised overclocker dudes like yourself don't want these for their tually monsters, but maybe they were slot 1 only way back then.

 

[Crashman]

Yep, how about that. Well, the problem was, it really didn't outperform the BX in most things, and the BX was cheaper, used cheaper RAM, etc. The BX is still an excellent solution, it runs fine at around 175MHz, but PC175 never really made it to the market

I couldn't afford a Tually PIII, and the Tually Celly I tried sucked. You can see what I did with an old Coppermine at my website?

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