P35 - X38 or X48 which do I buy

i have the same question. As far as x48, is it DDR3 only? Will the P35, even without PCIe 2.0k, be ok?

thanks for that, it cuts the choice down to 2. I have read reviews where the P35 preforms as well but it has always been with one card and they are generally older reviews. I assume there will have been bios updates by now to make the X38's run faster?
It is really frustrating..I had a clear idea until I started looking then it got a bit confusing with all the choice.

Is the X48 ASUS rampage not DDR2???

A good P35 board like the DS3L will serve you well until Intel releases their next line of processors (Nehalem) early next year which will require a new socket.

PCIe 2.0 shouldn't be necessary before you will need a new motherboard and processor, so don't worry about that.

X48 is not DDR3 only. In fact, X48 is little more than a glorified X38 rated for higher speeds and better timings.

One last thing, you don't need anything more than DDR2-800, even if you're overclocking. I can show you the math if you want  

Thanks I can get one of these locally. What is going to annoy me is, I was offered one of the DS3R boards with a Q6600 and 2 gig of Geil 800 memory for £250 but was a bit nervous not knowing the board...ah well some you win.
So the Reaper or Ballistix would be good enough at 800??

I agree with this 100%.

I noticed the D3Sl is not crossfire or SLi. I am looking to get a crossfire board. I did look at the P35 DQ6 from gigabyte but the sata connectors look like the 2nd card will stop me using them.
I watch alot of Hi Def films and my system stalls during play, I have been told told this will cease with the 3850 card due to the onboard decoding.
My current system will not play World in Conflict at decent levels with a 8800GTS 640mb so I will need the 3850 in crossfire to achieve a better result????

P35, X38, and X48 are all Crossfire compatible, but if you really want Crossfire you should strongly consider X38. It has 2 full 16x PCIe slots whereas P35 has one 16x slot and one 4x slot.

That 640MB GTS should handle WiC nicely. WiC is sensitive to processor speed; what CPU do you have?

Even current 8800GTs don't need/use PCIe 2.0, i.e. PCIe 2.0 is not something you need to worry about.

There have been plenty of tests where the difference between P35 and X38 is neglible at best, maybe 1%.

I'd say go with P35.

PCI 2.0 is for extra bandwidth and power input to the card, neither of which you will 'need'.

For Crossfire, what you WILL need is an X38. The difference between PCI 1 and 2 is negligible for now, but the difference between Crossfire in X38 and P35 IS significant and noticeable, even with two 3850's.

The reason for this is that not all PCI-E lanes are the same; they all have what is called an electrical speed, or sometimes bandwidth. For P35's, they ALL have ONE PCI-E x16 electrical. The ones that say they can run in Crossfire have a SECOND PCI-E lane, except it only runs at 4x electrical/speed. It's here that you are bottle necked, even with a 3850.

X38 boards generally have at least two PCI-E x16 lanes, which is what you want. Just double check the specifications (usually under "Expansion Slots") that when in Crossfire both lanes will run at 16x electrical (or at least no less than 8x).

Hope that helps! Check out some P35 vs X38 Crossfire reviews if you want more details/benchies on the differences. Two 3850's in an X38 run just about the exact same as a GTX, but when the 3850's are in a P35 you will see the GTX always win by a good margin.

Cheers

Notice how I didn't mention PCIe 2.0 when I recommended X38 for Crossfire. Even an old 975X board would be better for Crossfire than P35. Refer to Jevon's post for further explanation.

Edit: I'm not saying P35 is bad. In fact I consider P35 to be the best value chipset out right now, just not for Crossfire (which I don't generally recommend).

http://www.tomshardware.co.uk/PCI-Express-2-0-Crossfire...

Yes, since you have already purchased a 3850, forget about needing a PCIe 2.0 mobo…it is well known and as the Toms link above proves…this generation of GPUs wont utilize it.

IMO, if you are going for xfire (since you already have a 3850 you should) think x38 for the two PCIex16 lanes. 3850’s and 3870’s are projected to drop in price sometime soon (probably around the next NV release) and they will even mix if you want to step up to a 3870 + 3850 setup. Xfire also does quite well in general.

The gem of the x48 boards is the 4 PCIex16 support. You can’t use that feature until xfirex comes out and it isn’t known yet how well it will do since the drivers aren’t final. As a bonus though, when the x48’s come out…you might see a drop in price with the x38 mobo prices. That could be a consideration if you are on a tight budget. I would love to take a price cut and put it towards something else like RAM or a 2nd video card.

The choice really comes down to how many video cards you want to run. By time you stack up 4 3870's or 3850's, ATI and NVidia will have their next gen cards out that will potentially out perform 2 of whatever you have. I would suggest x48 only if you are going huge and want to pair up two 3870x2 cards.