Quad core weigh up help
 

My steam powered computer has crapped out on me for the last damn time. It's time to get a new main PC. However, some advice would be appreciated.

I'm fairly into hardware, so I like to keep up on the latest and greatest chips, hence I heard good things about Barcelona, then I heard many bad things about it and that CPU bug and the delays etc. What I haven't heard though is a direct comparison between (or even speculation about) Barcelona and Penryn with regards to sieving/LLRing.

From what I understand, Barcelona is native quad core which means there's less strain on the ol' HyperTransport bus, but it's kinda light on cache. The Intel quad core chip is essentially the result of two dual cores in a collision, a much less elegant design and placing considerable demand on the memory bandwidth, however despite that perhaps superior?

So, I'm asking, which would be better, a quad core AMD, or a quad core Intel? If I do go Intel, I would imagine that fast DDR3 RAM would be the order of the day and damn the latency, but I would like to hear the thoughts of others on this.

I've seen another thread in here about two quad core Xeons that basically maxed out with only three cores running, I can't say I'd like to throw down for a quad core and find it crippled like this.

Incidentally, I think I'll be waiting until there are some mid-range 45nm chips out from Intel (if I do go Intel), because the QX9650 is just ludicrously priced.

Barcelona's FP is stronger than Opteron's but it still is not up in the Core 2 territory.

While the bandwidth problem is an issue for Core 2, i thinks the 45nm Quads come with ridiculous amount of L2 (12MB i think) -- which should help quite a bit.

You might want to read this article: [url]http://www.theinquirer.net/gb/inquirer/news/2007/12/29/first-inqpressions-amd-phenom[/url]

Bottom line - get Penryn. :smile:

The Q9450 looks like the 'best bang for the buck' - 2.66GHz with 12Mb L2 cache for $316 (or thereabouts). The Penryn series will still have a memory bottleneck, but it may be somewhat relieved relative to the current Conroe cpus, because of the much larger L2 cache and the higher FSB.

As it concerns Prime95 testing, use a mobo with an Intel chipset (P35 or X38) rather than an nVidia chipset.

A truely integrated memory controller won't be available on the Intel cpus until the Nehalem series, which will come out sometime in 2009.

See this for a good discussion on this topic:
[URL]http://www.mersenneforum.org/showthread.php?t=9725[/URL]

Heh, OK, nevermind about that Barcelona then. A shame really, the quad precision would have been interesting to play with, not that I'm all that great with C.

As far as Intel then, yeah I was looking towards a 45nm equivalent of the Q6600, which seems to be the Q9450. It's a nice middle of the road CPU and the extra cache thrown into the mix is a nice bonus. I actually already have an E6600 in one of my machines and it's a stunning little worker.

Also, I have discovered that with a little overclocking it's possible to run the memory bus very fast indeed, so I was thinking maybe some PC2-8000 RAM (DDR2 1000). My motivation here is simply that DDR2 RAM is a lot cheaper than DDR3.

Here's the system I've got spec'd out currently:

[url=http://www.overclockers.co.uk/showproduct.php?prodid=MY-104-OC&groupid=701&catid=8&subcat=817]OCZ 4GB (2x2GB) PC2-8000C5[/url]
[url=http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=669220]Asus P5E iX38[/url]
Intel Q9450 (when it hits)
[url=http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=340995]Arctic Cooling Freezer 7 Pro[/url] (this'll freeze the balls off a polar bear)
[url=http://www.dabs.com/productview.aspx?Quicklinx=4XKB&CategorySelectedId=11137&PageMode=1&NavigationKey=11137,48070000,4294953243]Gigabyte GeForce 8800GT 512MB[/url] (currently none in stock)

I'll use the remainder of my current system to make up the rest, it's all pretty decent.

Ideally I'd like some faster RAM that's still 4GB, but without the price going up too much. If anyone knows of a better etailer in the UK for RAM I'd certainly like to know. Any other thoughts would be welcome.

Xeon X3000 series
 

[quote=lavalamp;121793]Heh, OK, nevermind about that Barcelona then. A shame really, the quad precision would have been interesting to play with, not that I'm all that great with C.

As far as Intel then, yeah I was looking towards a 45nm equivalent of the Q6600, which seems to be the Q9450. It's a nice middle of the road CPU and the extra cache thrown into the mix is a nice bonus. I actually already have an E6600 in one of my machines and it's a stunning little worker.

Also, I have discovered that with a little overclocking it's possible to run the memory bus very fast indeed, so I was thinking maybe some PC2-8000 RAM (DDR2 1000). My motivation here is simply that DDR2 RAM is a lot cheaper than DDR3.

Here's the system I've got spec'd out currently:

[URL="http://www.overclockers.co.uk/showproduct.php?prodid=MY-104-OC&groupid=701&catid=8&subcat=817"]OCZ 4GB (2x2GB) PC2-8000C5[/URL]
[URL="http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=669220"]Asus P5E iX38[/URL]
Intel Q9450 (when it hits)
[URL="http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=340995"]Arctic Cooling Freezer 7 Pro[/URL] (this'll freeze the balls off a polar bear)
[URL="http://www.dabs.com/productview.aspx?Quicklinx=4XKB&CategorySelectedId=11137&PageMode=1&NavigationKey=11137,48070000,4294953243"]Gigabyte GeForce 8800GT 512MB[/URL] (currently none in stock)

I'll use the remainder of my current system to make up the rest, it's all pretty decent.

Ideally I'd like some faster RAM that's still 4GB, but without the price going up too much. If anyone knows of a better etailer in the UK for RAM I'd certainly like to know. Any other thoughts would be welcome.
[/quote]Look into the Xeon 3000 series cpu's. They are cheaper, made better and just as fast as the Intel brand name. I have a 2.1 running at 2.6 with stock fan. Ran Prime95 for 24 hours, error free. Save yourself a couple hundred bucks. Got screens if anyone wants to see them.

Xeon X3210 ES. Lga775 Quad core
Crucial Ballistix Tracer(2x2GB) PC2-8500(1066)
Gigabyte P35-DS4 rev 2.0
Powercolor X1950XT 512MB
PC Power 1000watt PSU

Agreed about the CPU, I'm eyeing the Q9450 also... probably out in March if you can wait that long.

I'd go straight for PC8500 (DDR2-1066MHz) though. Goes for around 67 quid for 2GB [URL="http://www.komplett.co.uk/k/ki.aspx?sku=334571"]here[/URL]. Prime95 on quads is very memory limited - and is likely to remain so, even with the 12MB cache of the Penryn.

Unless you're aiming for maximum overclock, the Freezer 7 should be fine, especially since the Penryns run pretty cool. If you want to push things further, look at the ThermalRight 120 Extreme - but this costs quite a bit more, as you'll still need to buy a fan separately.

If you're more into DC projects than gaming, perhaps also look at a HD3870 512MB instead of the GeForce 8800GT. It's a tad slower, but you can also put that GPU to use when folding@home releases a client.

Don't forget a decent power supply.

In the past I've found the ATi graphics card drivers to be somewhat ... annoying, it's not any one thing that I can put my finger on, it's just how they are over all. However I looked into the HD 3870 to see what's what and it seems that it's basically a shrunken 2900, but in a lot of cases performs worse. It does have the redeeming feature that it supports DirectX 10.1, which nVidias next crop won't do, however 10.1 is only a relatively minor update over 10.0.

I have crunched in the past, and in fact I gave 7 CPU years to the United Devices cancer drug search thingamy before they packed it in. It seems that it is actually possible to fold on an nVidia card, [url=http://www.engadget.com/2006/11/18/nvidias-geforce-8800-can-fold-too/]at least for the G80 core[/url]. I'm not sure if the 8800GT can, but it uses the G92 core which is newer.

I think that in any case I'd have to go for the 8800GT since it outperforms the HD 3870 in pretty much every benchmark, uses less power and costs less. I really hope that AMD can pull out of this dive, I'd hate to see things stagnate from lack of competition.

That RAM you linked to is certainly curiously cheap, a shame it's only 2*1GB since I would prefer 2GB modules to leave room for future expansion. I'll take them into consideration though, since 1GB modules may have more headroom for an overclock.

Speaking of overclocking, I'm not aiming for a maximum CPU overclock by any stretch, just a little extra bang for my buck, and the Freezer 7 fan should be able to cope with the extra heat dissipation. As I said, the rest of my system is decent enough, in particular the PSU is a Seasonic S12 600W.

I'm currently using my Core 2 Duo PC as a replacement for my main PC, but it only has onboard graphics so I couldn't use this for any extended length of time. I have to have my games! The end of march would be about the limit of my patience, however I had read that the Q9450 was due out mid January. Sadly the next line of nVidia cards have been pushed back _again_, so it seems they'll arrive too late for me.

Unfortunately, the rumours are that we'll not see the 45nm quads until March. See [URL="http://www.digitimes.com/mobos/a20071218PD212.html"]here[/URL].

As for the 8800GT, it won't be able to fold. It's not an issue of the hardware, but nVIDIA's drivers do not return accurate results that FAH needs. Since we're limited by the memory bottleneck with multiple Prime95s, my plan is to run Prime95 on 3 cores, then use the 4th core and GPU for folding.

Given the different cache usage, a potentially useful combination could be:
Core 0 - LL Testing
Core 1 - Factoring
Core 2 - LL Testing
Core 3 - Factoring

Each 6Mb of the cache would be virtually available for the LL test, as the Factoring work doesn´t really make great use of it. This would ease the mem bottleneck referred in several posts. I don´t have figures to support my claim, though.

[QUOTE=lycorn;121969]Given the different cache usage, a potentially useful combination could be:
Core 0 - LL Testing
Core 1 - Factoring
Core 2 - LL Testing
Core 3 - Factoring

Each 6Mb of the cache would be virtually available for the LL test, as the Factoring work doesn´t really make great use of it. This would ease the mem bottleneck referred in several posts. I don´t have figures to support my claim, though.[/QUOTE]
Another possibility would be to crunch projects that aren't specifically connected to Mersenne Forum. There are plenty of projects, math included, that have low cache utilization.

OK, after giving serious thought to the matter, I've very reluctantly decided to wait until Intel releases their new Nehalem core.

Native octocore design, onboard memory controller, memory access via QuickPath not the FSB. It's just so much of a big update, I can't turn it down.

In the mean time, I may hold on for a mid-range GeForce 9 graphics card for this PC so that I don't go completely insane.