New rig processor quandry...

[Albuquerque]

Rig is used for gaming (of course!), 720P video encoding / transcoding, 12mpx raw-format photo editing and batch processing / conversion to PNG, watching movies on occasion and of course surfing the web.

I have already purchased a PCI-E raid card and a stack of SSD drives to populate it. I'll be buying at least one high end video card (although I'm waiting for NV to release Kepler before I make any decisions), 32Gb of ram, and likely a dedicated PCI-E audio card. I'll also be picking up a Dell U2711 monitor to view it all. I already have the case and PSU and home-build water loop.

So, for the processor, I'm thinking I have two obvious options:

#1: Sandy Bridge "E" 3930k on the X79 platform. 6-core, 12-thread, unlocked, quad-channel ram interface, and 40 PCI-E lanes. Most people can get more than 4.5Ghz out of these with any semblance of reasonable cooling, it has enough PCI-E lanes to not choke on the RAID and a high-powered video card or two, and quad channel ram is sexy!

#2. Ivy Bridge 3770k on the Z68 or perhaps Z77 platform. 4-core, 8-thread, unlocked, dual-channel ram interface and 16 PCI-E lanes. The limited number of PCI-E lanes is what concerns me here; a fat RAID card with a stack of SSD's has been known to break video card stability when the PCI-E bus gets REALLY busy.

Obviously #2 is going to be about $300 cheaper than #1, but I just shelled out a pretty decent stack of cash just for the RAID array. In the grand scheme of things, this will probably be less than a 10% difference of the entire cost of the box.

I also assume that #2 will probably overclock further and create less heat while doing it, so maybe the raw performance difference can be minimized. And perhaps the PCI-E 3.0 lanes that are on IVB will help alleviate the bus contention issues that some sites see with massive bus traffic causing the video cards to crash...

Thoughts?

 

[V3]

I say go with option one. If you want something cheaper the i7-3820 could be an option. I'm sure there will be a 22nm LGA2011 somewhere down the line to upgrade to.

 

[shiznit]

For gaming, you will see little if any benefit from the Sandy Bridge E. The money saved can buy a better GPU.

Ivy Bridge is PCI-E 3.0 so you can get away with only using 8 lanes on with a 3.0 card and the DMI bus from the south bridge has plenty of bandwith for I/O. As for your RAID plans, why do you want your SSDs on a hardware raid card?

 

[I.S.T.]

Given your photography and video editing work, option 1 is by far the best choice.

shiznit, you're assuming the card is PCI-E 3.0. I highly doubt it is, that's very new.

 

[shiznit]

Yea I missed the part where he already bought the card. I don't do much photo editing and I usually do something else while waiting for transcoding to finish so it's hard for me to see value in slightly faster times. As for photos, I have no idea how much horsepower editing takes but isn't that GPU accelerated now anyway?

 

[Bludd]

Based on the money you are already spending, go for option 1 if you can afford it. x264 is going to rock on 12 of those threads.

 

[shiznit]

On second thought, if you can afford it (and you already bought the SSD array), might as well go all out especially if you need more than 16GB ram.

 

[Albuquerque]

It might be useful if I could somehow 'limit' one of the PCI-E interfaces to only use 8x, but I'm not aware of an option for that. If I plug a 16-lane device into a 16-lane slot, it's gonna soak up all sixteen lanes. The RAID card is an 8-lane device, and that's where I get confused as to how the breakout really works. I've effectively oversubscribed the board at that point; maybe it goes into a default 8x / 8x mode by using them both? Actually, I believe that's how it truly works.

For gaming, it surely isn't going to matter for that many threads. The only reason SB-E is interesting is because of the excess of PCI-E lanes to allow for RAID and video card (or more than one card in the future.) And they seem to overclock nearly as well as their current SB smaller brothers...

 

[shiznit]

If the board has 2 PCI-E slots that share 16 lanes, as soon as you populate both, they switch to 8x/8x even if one of slots is only running a 4x card.

Server motherboards like the Supermicros I use for my ESXi and storage servers allow for more flexible setups (8x/8x/4x) and even route an extra slot or two through the DMI bus but consumer/gamer motherboards are generally 16x or 8x/8x.

If your gpu pci-e 3.0?

 

[Albuquerque]

Haven't decided on GPU yet. Given existing information, extra PCI-E bandwidth (ie, over 8 lanes of 2.0 interface) doesn't seem to matter much anyway.

 

[shiznit]

the Z77 chipset (Z68 too supposedly) for Ivy Bridge will do 8x/4x/4x. If you get a 3.0 gpu, 8x will be plenty, at least for a good while. 4x is fine for your raid card, even in 2.0. You will still have another 4x to spare, and if you don't need it, your raid card will get the full 8x.

 

[Albuquerque]

the Z77 chipset (Z68 too supposedly) for Ivy Bridge will do 8x/4x/4x. If you get a 3.0 gpu, 8x will be plenty, at least for a good while. 4x is fine for your raid card, even in 2.0. You will still have another 4x to spare, and if you don't need it, your raid card will get the full 8x.

There's no way four PCI-E lanes will be fine for the RAID card with six SATA3 SSD's attached to it. We're talking about speeds approaching 3Gbytes per second; four lanes will never do that.

I need eight lanes for the RAID without question, and eight lanes for the video card -- leaving me exactly none. PCI-E 3.0 might help for the video card, but insofar as I'm aware, there are no RAID cards with support for PCI-E 3.0 yet... And the one I just bought isn't using it, either.

 

[PixResearch]

Option 1 here. The 6 core sandy bridges are excellent if you have the workload for them. Transcoding and image editing can spread out across all the cores easily enough and 4.5GHz is no problem at all. 25% overclock with conventional cooling is easy to achieve if you can live with the fan noise.

What I can't quite work out is what the SSD raid is for. None of your listed use cases are disk bound... I can certainly see the benefit of having your OS and main apps on an SSD and better still 2 of them in raid 0 but 6 implies there's some other task that will benefit. It seems odd to spec those then consider spending less on a CPU.

I've built a couple of SSD raids now (for streaming uncompressed video at 120fps) and even expensive external raid controllers start becoming a significant bottleneck above 3-4 drives...

 

[shiznit]

4x 2.0 lanes is 2 GB/s, probably a little less than your 6 SSDs will peak at but still a huge amount, and even with 8x the processor on the controller itself may become a bottleneck before your SSDs do.

But the simple answer is, if you don't want to make any compromises, you have to go with Sandy-E.

 

[Raqia]

I'd wait for IVB overclocking reports before making a decision if I were you. However, either of those are ridiculous overkill for most purposes; I was tabbing between 6 3-D games, 1 GPU demo, and watching an HD movie simultaneously on my 2500k w/o trouble.

 

[hoho]

Trust me, once you start some hardcore photography you'll be capable of using up any processing power you have access to. E.g putting together a time lapse from 30k images with minimum amount of processing took around 40h on q6600. Sure, it's an old CPU but even the 6-core monster here will quite likely take several hours to do the same work

 

[Blazkowicz]

32GB ram will be cheaper with 4GB sticks than 8GB sticks, so the expensive 2011 mobo pays for itself. though I've just checked and the 8GB sticks seem to have got very affordable - their price has crashed without notice. duh

option 1 with maybe a 3820 is nice as you just build it right now rather than wait for two monthes. use whatever crappy GPU in the interim. we've known Intel, and no CPU will have its price lowered. ever.

 

[shiznit]

+1 for the 3820, great deal.

 

[Davros]

I was tabbing between 6 3-D games,

I pride myself at being good at games, but 6 at once seriously ???

 

[hoho]

Hey, I multiboxed 5 copies of WoW on a measily 6600GT and C2D with 2GB of RAM under Linux. Running 6 games in parallel doesn't really say all that much if you "forget" to mention what they are. Not to mention tabbing out of one basically means it won't be using up any GPU and often CPU power either.