I have rambus 800mhz will it work with 850E?

[NYRanger99]

I'm confused what motherboard to get. I have no idea if it would work with the new 850e Chips 533mhz mb. if it does would i benifit from it only using rambus 800mhz. Should i just save my money and buy a 850 400mhz board? Please help

 

[shathal]

Yes, 850E will quite happily work with PC800 RIMMs.

The think that 850E "can" do (Intel hasn't validated PC1066 RIMMs on it) that the 850 can't do is to use (good quality!) PC1066 RIMMs.

I'd definately go for 533 FSB on the CPU, so 850 is good anyway. PC800 is fine either way .

Hope this helps you with your question.

- Shathal.

 

[Bellyofthebeast]

You didn't say exactly what rdram 800 you have or what size & speed? Is it 800-40ns or 800-45ns? What manufacturer? What size modules? ECC or non-ECC?

Yes, it could make a big difference in choosing your 850E board.

I will say that my old board, Abit TH7II (850), OCed great with Samsung ECC rdram 800-45, 512MB modules, both 4X & 3X along with fixed pci/agp bus values were selectable in Bios menu. It was possible to OC easily an extra 400 or more Mhz on AIR cool. I used P4s, 2.0, 2.2, 2.4, 2.53. Actually, the 2.2Ghzer was incredible, the 2.4 very disappointing.

Next, the interesting part. I got a hold of 1066 drcgs from TI & had them professionally soldered into the TH7II board, replacing the lower clocked ICS drcgs. In spite of not having the best possible bios (Abit hasn't upgraded bios for 533 bus or 1066 timings.), the same rdram memory performed even better, & came very close to a stable 3Ghz with a 2.2cpu & easily hit over 3ghz with a 2.53, AIR COOL ONLY. (& Forget the 2.4)

This little exercise answered the question for me. Yes, rdram 800 does work well with the 850E chipset. So, you can start with the 800, you have now, upgrade later, when much better yields of 1066 or 1200 will be available.

The catch is, Kingston rdram doesn't act right on the Abit TH7II, many problems. Samsung rdram seems to work best in this scenerio. I really believe the ECC helps for more stable OCing. Some will say, "there is more OC headroom" using non-ECC. In my testing, that extra headroom was not worth the added instability, at whatever FSB, you're trying to achieve.

A final word concerns the slot configuration used. Whenever using slots1&2 with rdram & slots 3&4 with crimms, that produced highest bandwidth peformance, no question, especially with the rdram 800 as opposed to the 1066.

Now, using Gigabyte 8IHXP board with Kingston ECC 1066-32 rdram, 2X256MB modules.
Currently run very stable at FSB 150: 13798 3D marks

When using the ECC Samsung 800-45 rdram, with this board, it's possible to run stable at FSB 156 with AIR COOL, something not possible with the normal original drcgs of the TH7II on AIR ! 2.53@fsb156 & Samsung 800-45 rdram as described produced: 13025 3D marks!

If I had known the ECC Samsung 800-45 worked so well in a 850E board, I wouldn't have bothered to get the 1066, but all this really came to light through testing, having both 800 & 1066 rdrams & actually 3 boards (8IHXP, TH7II, TH7II-drcgs mod).

There you have it. By the end of the year, I suspect we'll finally get some high yield Samsung 1066 rdram, which can only improve matters. With good 800 & the right board, you can aford to wait for the best 1066 rdram later on.

OCZ 800 or 1066 rdram doesn't work right on many boards, including the GA-8IHXP & TH7II.

 

[lopri]

I got 8IHXP first then PC1066 shipped the next day, so I tested the setup with my old PC800 RDRAM (Samsung, Non-ECC, 45ns, Double-sided) before the new ram arrived.
When tested, they (8IHXP and PC800) ran nicely together with my 2.26GHz. FSB at its stock speed (133MHz), no stability issue. However, when I ran Sandra, the PC800 didn't give me the bandwith of PC1066..? I got exact 800Mhz bandwith with those modules. I was a bit confused cause I thought the memory was overclocked (in order to cooperate with the CPU) - but actually it wasn't. Did you test your memory bandwith by any chance (with 8IHXP), Belly? I'm curious cause I now have 2 pieces each, PC800 and PC1066. If PC800 can produce the same bandwith (as PC1066's at FSB 133MHz), I will merrily use all 4 modules on my system. (1GHz ) Is it possible?

Thanks in advance.

 

[lopri]

Anyone?

 

[Bellyofthebeast]

If you use 800 & 1066 modules together, the mobo will default to the speed of the lower 800 modules. This is documented at Gigabyte. In fact, no mobo I know of, will run both 800+1066, at the 1066 level, how could it. One runs at 3X & the other at 4X multiplier.

The 800 will OC nicely between about 900-1100, on a practical basis. The 1066 is running at 1200 on current setup, fsb@150 or 1184 with fsb@148, for example. However, to get a 3Dmark score at fsb 150 using 1066, you'd have to run fsb 156 with 800, approximately.

Using same cpu, etc.:

Bandwidth with 1066, fsb@150...Sandra score ~3700-3800s

Bandwidth with 800, fsb@150...Sandra score ~3100-3200s

The GA-8IHXP has a Bios menu choice where you can slightly OC the memory as well, however, not used in testing shown.