What ram do I get ??

[wap3]

Me again

I have a P4 1.7 pc machine and I need some more ram. I only have 128mb and would like alot more perhaps another 256mb.

According to the oringal specs for my machine it is rdram.

So my question is do I have to buy rdram or can I get something else ??

I want to get it from e-buyer along with some other stuff so if someone would like to help me even more and point me to the right stuff on there I would be very grateful.

:D

[mouse]

PC800. Make sure you've two spare slots as RDRAM operates in pairs (although I think it'll come in pairs so no need to buy twice ;))

[wap3]

:confused:

PC800 whats that

Sorry im dumb with this kind of stuff.

Do I have to buy rdram cos it is very expensive can I not get anything else ??

:o

[oracleguy]

Originally posted by mouse
(although I think it'll come in pairs so no need to buy twice ;))

ehh... I dunno I've seen lots of places that sell it by the stick so it doesn't look so expensive.

And yes you have to buy RDRAM... see there are different types of memory based on the model motherboard you have. There is SDRAM, DDR, and RDRAM and they use different types of slots, so you can't mix types of ram.

PC800 is one of the types of RDRAM. RDRAM was invented by a company called RAMBUS. Its very fast memory although it usually costs more and you normally should run it in pairs.

If you have 128MB of ram, then most likely there is two 64MB sticks of RAM in the computer right now. You should look in your computer documentation to see how many memory slots you have on your motherboard. If there is only two, you are going to have to replace your existing ram. If there are 4, and you want to add 256 on top of your existing 128, you need to buy two 128MB sticks of memory.

If you have further questions please ask.

[mouse]

It's rdram ;) Ebuyer don't seem to have much in the rdram way except 512mb kingston for an extortionate amount.

Ocuk have better prices at £74.03 Including VAT for 256mb and £135.13 Including VAT for 512mb http://www.overclockers.co.uk/acatalog/Online_Catalogue_Samsung_146.html

Sadly rdram is expensive stuff, I use it myself, think mine was about £100 per 256mb pair.

^^ as Oracleguy says ;)

[wap3]

Ah ok that clears it up.

I have three slots at the moment. One is filled up giving me 128mb. So I have to slots left.

In theory now then I should try and buy 512mb if I can afford it seen as it will take up the remaining two slots ?? that about right.

:D

[Jason]

Its not necessisary to buy 512mb RDRAM but for the future, if you need to upgrade your RAM you would have to replace whatever is in there with the two new sticks. So going with 512mb RDARM isn't a bad idea but its expecive as previously said. But then again, you could put in your 256 and later replace the other two sticks of 64 each to get more. Its really up to you and your budget.


Jason

[mouse]

HOLD ON?! you have three slots on an RDRAM board? :confused:
Now I'm confused; RDRAM with the P4 operates in pairs, the only exception {to my knowledge} are a few more recent boards that use 32bit PC1066 rimms which I don't think you'd likely be using with a 1.7 chip. Single channel RDRAM on a P4 would be silly tbh as it'd only provide half the P4's desired 3.2gb/s bandwidth...

Um, could you post some information, like the chipset or motherboard model. The chipset info can be deciphered from Device manager => System devices from the processor to I/0 controller and processor to agp controller. Mine starts Intel(R) 82850 indicating the i850 chipset, I'd asume your to be the same. OTherwise I cant see how you can be using RDRAM tbh.

:confused:

[Sparky]

Obviously depending upon finding out what motherboard you have, and thus what ram would be best, might be worth checking out Komplett (http://www.komplett.co.uk/k/kl.asp?AvdID=1&CatID=17&GrpID=2&t=483&l=2), or alternativly you could do some quick searches yourself here (http://www.computerprices.co.uk/) and here (http://www.pcindex.co.uk/).

[wap3]

oops . . sorry my mistake I thought I had three but I do in fact have four.

;)

Ok so I think I will end up ordering 512mb from somewhere cos it will be better in the long run I think.

thanks

P.S Mouse you do have the same motherboard as me :cool:

[oracleguy]

Then you should be able to add two 256meg sticks or two 128meg sticks... doesn't matter so if you add 256meg sticks you'll have 640megs of ram and with 128meg sticks you'll have 384.

Just depends what you can afford.

[wap3]

Hi guys

I got another question about ram.

If a system has a 64mb stick of SDRAM PC100.
Do I have to buy extra sticks which are 100mhz i.e. PC100 or can I buy 133mhz i.e PC133 ??

Does that matter so long as they are SDRAM ??

:thumbsup:

[mouse]

I see no reason why it wouldn't work just fine.

[oracleguy]

Yeah you can mix PC100 and PC133, the faster stuff will slow down to the slower stuff. However if the system bus is only 100Mhz then even if you got all PC133, its only gonna run at PC100 speeds.

[Roy Sinclair]

If you have a PC100 system, adding PC133 may or may not work. Some motherboards will accept the PC133 memory while others will choke. Do a little more searching, you can find memory which is PC100 or find one of the PC100/PC133 DIMMs which are specifically designed to work at either speed.

[wap3]

Ok great

So I will get 100mhz then if thats the case.

One more question :

When looking for this memory, I keep seeing different things attached to the end of the product description.

For example:
- registered ECC
- DIMM
- non ECC

could you tell me what these all mean please.

thanks

:thumbsup:

[mouse]

The difference between ECC and non-ECC is error checking. non-ECC has a pairty bit that travels in parallel to every 64bits (I think it's 64 these days) and is generally for really old stuff in the days where ram errors were prevailent and in mission critical machines. Ram these days is pretty good and non-ECC is generally used, there is error checking on the memory controller anyway, so this is what you'll be getting I'd guess/assume.

Dimm just means, Dual In-line Memory Module, and is the physical format for SDRAM.

[Roy Sinclair]

Here's (http://www.buyaib.com/memoryfaq.html) a FAQ on memory, it should help.

[wap3]

ok thanks

Great help guys !!

:thumbsup:

[Roy Sinclair]

Originally posted by mouse
The difference between ECC and non-ECC is error checking. non-ECC has a pairty bit that travels in parallel to every 64bits (I think it's 64 these days) and is generally for really old stuff in the days where ram errors were prevailent and in mission critical machines. Ram these days is pretty good and non-ECC is generally used, there is error checking on the memory controller anyway, so this is what you'll be getting I'd guess/assume.

Dimm just means, Dual In-line Memory Module, and is the physical format for SDRAM.

No. ECC memory is the good stuff, parity memory is the "plain" stuff and non-parity memory is what Apple computers ought to go bankrupt for foisting it off on their users.

ECC memory has several additional bits on each word of memory which can be used to detect and repair any single bit error and detect any two bit error, system with ECC memory can continue to process if a memory bit goes bad. This is important for system critical work and any system set up as a server should always use ECC memory.

Parity memory is the next step down from ECC memory, it can only detect a memory problem and when a memory error is detected on systems using parity memory the OS should either mark the indicated memory bad and not assign it for use any more (a few OSes will do this) or crash the system (most OSes do this) to prevent whatever data got corrupted from being used or saved.

Apple memory and non-parity memory is the bottom of the barrel, no memory errors are ever detected and corruption of your data and/or strange program or system crashes are the order of the day on computers using this kind of memory.

The reliability of memory has certainly improved a lot but it's still not reliable enough to depend on it not having a problem and memory that won't tell you that a problem exists is still a poor choice.

Personally, I think all memory ought to be ECC simply because the lesser stuff can't be relied on and the cost difference really isn't that big.

[mouse]

Yes, I'm incorrect there, the point off ECC is that it uses more than one bit for error checking and it can repair some errors. I agree to an extent on it being more widespread; we use 64bit datapaths whereby it takes no more bits to use parity or ECC, so why not go with the safer ram? I suppose the thing is; if current ram is outperforming it on speed and performing adequately errorwise, then why bother with the added expense of ECC?

I'm yet to test the effect of running in ECC, might give it a bash later and bench it. I'm guessing there's 1 or 2 cycles of latency added...

[Roy Sinclair]

ECC is handled in the hardware and the paths for it are well know and well optimized so it comes with *NO* extra time penalty for memory access. It's a 1970's technology and the only reason early PC systems used parity memory instead of ECC in the first place was because of the high cost of memory back then. The relative cost of adding the extra bits for proper ECC is considerably lower these days.

I was maybe a little rough on Apple but I've never understood their decision to not even check parity, I've seen far too many memory problems in PC systems to expect that Apple systems would have any better luck. It makes me wonder how many Mac users are suffering through data/program corruption and have no clue why their system doesn't work properly.

A couple years ago when I was working part time in the tech department for a major retailer I also noticed some memory which worked in systems which required parity memory but they had a simple chip on the memory sticks which generated the parity bit as the memory was read instead of having the full memory chip to provide a real parity check. That's even worse than no-parity memory IMO because a novice user may not understand what it means.