Z77 Motherboards for SLI 680

iiDeadSeriousii

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I'm looking to overhaul my rig from an AMD build to an Intel build. Currently I have an FX-6200 paired with an ASUS Sabertooth 990FX and an EVGA GTX 680. I'm looking at the i5 3570k and will be definitely adding another 680. I have nothing against AMD it's just that my Sabertooth doesn't support PCI 3.0 (it only does PCI 2 at dual x16). The front runner so far is this MSI board:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130643

But it clearly says x16, 8, 4 for PCI 3.0

My board has the same bandwith limitation but it's PCI 2.0, I've heard that with 600 series, especially when SLI'ing and TRI SLI'ing, that the PCI 3.0 vs 2.0 difference starts to show itself at that point. Is there a better board for my SLI needs?

Current rig

FX6200 OC'ed to 4.6 with Coolermaster Hyper 212
ASUS Sabertooth 990FX
Corsair Vengeance 8GB 1600mhz
EVGA GTX 680
Corsair HX850 PSU
Coolermaster 922 HAF with 4 case fans
 

iiDeadSeriousii

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Yea that's currently my 2nd one. I don't really want to spend $200 so if it ever dropped down to 160-180 range, I'd pick it up for that. The MSI one is actually $144 from Amazon so that's why in terms of price and performance it's far and away the best choice.

My big concern is the PCIe bus bandwidth. I'm not entirely familiar with the difference between x8, x8 or x16, x8 or x16/0. Particularly that last one. I know more is better obviously but I'd like to know if anybody has some benchmarks to show me how it benefits SLI since all I could find dealt with single card setups.
 

Mozart25

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That's untrue and off-topic, as the OP is going SLI, and according to posts I have seen on Reddit and DSLReports, the disadvantage of 3.0 @ 8x or 2.0 @ 16x starts at just under a 10% loss at 1080p, up to 50% loss @ three 1080p monitors.

The article you linked is only comparing a single card at the different PCIe speeds, and the difference becomes much more dramatic once you add a second card:

LfrMUIu.jpg


Sources:
http://i.imgur.com/4jAHC.png (BF3 w/2x 680 SLI)
http://www.dslreports.com/forum/r27982324-Very-Specific-Math-Based-PCIe-3.0-Question

In conclusion, the OP should either stick to a single card if he is going use LGA1155 above 1080p, or switch to an X79 build so he isn't constrained to 1080p on SLI.
 

iiDeadSeriousii

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This is probably exactly the answer I was looking for. I looked at x79 builds and wasn't too familiar with them so I decided to stick a little more conventional and go with LGA1155 CPU's like a 3570k. I did intend to eventually jump to 1440p at some point but wanted to redo my CPU/MOBO first before going with the 2nd GPU and new monitor.

What's a good x79 combo? After looking around a little I'm kinda disappointed there's no i5 3570k equivalent for x79. I don't mind it being a little expensive (I'd prefer to keep it under 600 for BOTH the CPU and MOBO). And sorry for asking another question within this thread, I'd just rather have it answered here instead of starting a new thread. Thanks in advance guys.
 

Mozart25

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The i7-3820 can be overclocked substantially, despite not being unlocked. Don't let that fool you.

The Asrock X79 Extreme 3 or 4 is only $190-$210, and a very good value for the money.

The i7-3820 is $230 if you live near a Microcenter, $300 from Newegg.
 

iiDeadSeriousii

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From what I can gather the pro's/cons of the x79 chipset are:

Pros:
-Able to support 64gbs of memory
-PCIe 3.0 with more lanes available (x16, x16, x16, x16) is possible
-No "low end" boards
-Overclocking is supposedly easier.

Cons:
-Price, most boards I've seen start around $200
-Niche market, not as many people have one so finding help/troubleshooting one will be a little tougher
-Could potentially be a dead-end socket? The LGA2011 I mean.
-The CPU market consists of the $230-300 i7 3820 and then the next compatible chip starts at $500+.



I've been looking more into the i7 3820 and it is a very nice CPU for its price, but taking the boards into consideration (I price checked with an ASRock Extreme 6) and for a compatible 3570K build with board the price comes down to:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130643
$164 on Newegg (Or 145 from Amazon)

http://www.newegg.com/Product/Product.aspx?Item=N82E16819116504
$229 on Newegg (Or 219 from Amazon)

Total of $364-395

vs the x79 build:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813157289
$219 on both the egg and amazon

http://www.newegg.com/Product/Product.aspx?Item=N82E16819115229
$299 on Newegg (279 on Amazon)

Total of $498-518.


This may obviously seem like a no brainer question but is that bigger buy-in price worth it? Am I going be to left holding an obsolete board in about a year or so if I buy into the x79? Should I wait for Haswell which will more than likely be sitting in between those prices? I'm not in a terrible rush to wait, but I've heard we won't see anything until June-ish for Haswell.

It seems like I'm asking a lot of questions but you seem like a knowledgeable guy Mozart, thanks for the replies.
 

Mozart25

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Ugh, that article is comparing two and three-way GPUs on LGA 1155, which means that the only time you get 16x lanes--on PCIe 2.0 or 3.0--is in a single card configuration.

The whole article is then wasted, by comparing mainstream chipset to mainstream chipset.

No one I know is asking if their purchasing decision is between a Z68 or Z77 motherboard. The *real* question at hand is if X79 (being able to run dual GPUs at 16x/16x) is worth the premium over Z77 (running dual GPUs at 8x/8x). The article doesn't even approach the benefit of running two GPUs at full speeds.

To put it in perspective, a Sandy Bridge build running three GPUs are going to run at 8x/8x/4x @ PCIe 2.0, which is equivalent to PCIe 3.0 lanes running at half as many lanes.

No enthusiast worth their salt is going to run high-end GPUs on such a bottlenecked board.

They really should compare x58 (16x/16x @ 2.0) to Z77 (8x/8x @ 3.0) to X79 (16x/16x @ 3.0) if they want someone to take the article seriously.
 

Mozart25

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The 3820 is the same price as the 3770K at Microcenter ($230), so the real difference is between mobos--about $120-150 for Z77, and $200-250 for X79, so you're really considering if $80-100 more is worth the extra bandwidth. I say it is, but it's a choice you have to make.
 

Mozart25

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Whether or not the OP buys at Microcenter, the costs are equivalent.

The i7-3770k (quad core + HT) is $320 on Newegg, the i7-3820 (quad core + HT) is $300 on Newegg (and $280 at Amazon), so the X79 CPU is actually cheaper than the Z77 one.

The graph I posted showed a 10% loss at 1080p with a two-way setup. I think at this point, if the OP is sticking with two cards, which chipset he gets is really determined more by his resolution. But even at 1080p, he should have at least a 10% improvement, and that starts scaling drastically once you go to 3x 1080p monitors or higher.
 

Mozart25

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It's worth it at triple monitor or possibly even 1440p (why I made the graph--if the loss is only 8% at 1080p, but 50% at 3x 1080p, what is it at 1440p? I approximated at least 26%).

Then again, is spending $50 extra initially worth 8% more FPS at a single 1080p monitor? The case is admittedly weak, but newer games are on the horizon (Crysis 3, Star Citizen, Cyberpunk 2077, Witcher 3, etc.) that will be more punishing than BF3. And whose to say he sticks with a single 1080p monitor? Prices are great on LCDs and it's understandable if the OP wants to set himself up to go with a 1440p or 1600p monitor or 3x 1080p ones.

Being able to buy an X79 now with SB-E, and then drop an IB-E CPU into it in 18 months or so when the CPUs hit its stride, is a benefit in my eyes. IB (1155) is going to be replaced with Haswell in a mere four months. It's not "future proofing," but giving yourself a logical upgrade path.
 

iiDeadSeriousii

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Thanks for the debate guys, it's really helped in the decision making process. I actually DO live pretty close to a Microcenter. There's one in Boston about 45 minutes away. Going the z77 route that way will net me a 3770k for $230 and I can pick up an MSI GD65 which I've been eyeing for a while at 165. That puts my total around $400 with taxes.

The X79 option is still very temping due to the higher bandwidth it will give me. The i7 3820 is around $280 and the ASRock Extreme6 I'm planning on pairing it with is around $219. That gives me a total of around $500.

One last thing, I have absolutely decided I'm going with 2560x1600. I will be getting a Crossover 30Q5 in the next few months. At this point, the extra $100 seems worth it but I have one last question. When IB-E releases will it be on a new chipset/socket? Or will I be able to drop one of those in my ASRock I buy?
 

Mozart25

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I'd just like to throw in that the i7-3820, if you get it from Microcenter, is also $230 in store (same price as the 3770K):

http://microcenter.com/product/383144/Core_i7_3820_36GHz_LGA_2011_Boxed_Processor

At 1600p, I would most definitely go X79 with a dual-GPU setup. That is ~4.1 million pixels and you will lose significant bandwidth at 3.0 @ 8x lanes on Z77 compared to 3.0 @ 16x on X79. Referencing the graph I posted above, you are looking at a 28-30% increase in framerates by going X79.

Given that the 3770K and 3820 are the same price, the only difference is in terms of motherboards. I would think that's a very good bargain for the extra performance. Where else can you increase your framerate by nearly a third for only an extra $50-100?
 



Your statement is incorrect.

The Z77 Motherboard they used in the article supports PCIe 3.0 x16/x16 SLI. There are quite a few out there that do support x16 SLI using PLX chips.

They are in fact showing a true comparison between PCIe 2.0 x/16/x16 and PCIe 3.0 x16/x16

GTX 680's *barely* saturate PCIe 3.0 x8 so even if they were dropped to x8 they wouldn't have a noticeable impact on performance as 5% decrease + 85% increase averages out to an 80% increase over single card.

If you look at this article you can see that there is almost zero performance difference between x16 and x8 ( I realize it is based on the HD 7970, but both cards are close enough in performance that the results would be similar. Plus the AMD card actually has a higher memory bit width (384 vs 256) so it should affect the GTX even less than the 7970)

Another note. While the it-3820 *is* overclockable, you have to solely use BCLK instead of Multiplier changes, which can have very different results. While it is possible to get to 4.5GHz, you are going to need substantial cooling, and a lot of tinkering to get there. It is much easier to get the 3570k OC'd due to the unlocked multiplier.

There is no reason to pay the premium for X79, unless you have the budget and want to go for it. Gaming performance will be just as good on Z77. If you are worried about PCIe lanes and throttling, get a PLX board, like the Gigabyte Z77X-UP7, but then again you are paying a price premium.
 

Mozart25

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Sorry, that's not true 3.0 x16/x16 if you are using a PLX chip, which is a poor bandaid trying to remedy Z77's PCIe limitations.

I could spend more time on this, but will direct you to http://www.overclockers.com/forums/showthread.php?t=711837


Whether or not you saturate 8x or 16x is heavily dependent on your GPU, your resolution, and the game you are playing at (it's mentioned in that topic that BF3 will be throttled at 8x). For 1080p, the tested loss is really only 8% (see the graphic based on the information from Reddit). For 1440p, it's estimated to be 26%, and for 3x 1080p, it's estimated to be close to 50%. This is all in BF3 with twin 680s, so it might vary a tad for 7970s.

Lastly, the "premium" for X79, in the OP's case, is only the difference between a Z77 and X79 mobo. The CPUs cost the same.
 
You are right, it does not magically add lanes to the system.

However, in an SLI setup, the CPU sends the same data to both / all cards, the different cards just only render 50% or 33% of the frame (depending on 2way / 3way) And then the information is combined when it is sent back to the CPU.

What the PLX chip does, is instead of making the CPU split the transmission / receive feeds to the cards, it receives a single full speed output from the CPU, and then splits the data out. Then receives the data from the cards, and combines it into another full speed stream back to the CPU.

Yes, the PLX chip does add some overhead, but it is usually measured under 2% of a difference.

The following page benchmarks 2, 3 and 4-way SLI setups using Z77, Z77+PLX and X79. And the results are all fairly similar, until the non PLX boards start going to x8/x4/x4 or x4/x4/x4/x4

Yes, the PLX is a bandaid, but it works. But for 2-way SLI x8/x8 is more than enough. There is no reason to go for an expensive X79 board if you are doing 2-way. If you are going 3 or 4-way then it's a toss up as both solutions are expensive.
 

Mozart25

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We're going to have to agree to disagree in our opinions about which chipset is better for dual GPU configurations. The (admittedly anecdotal) tests done on Reddit in BF3 with twin 680s do indeed show a difference between PCIe 2.0 @ 16x/16x (equivalent to 3.0 @ 8x/8x) and PCIe 3.0 @ 16x/16x--how big of a difference depending on your resolution.

The evidence posted showing that PCIe 3.0 @ 8x/8x as allegedly equivalent to PCIe 16x/16x was done using PLX, which becomes circular reasoning, so I would not lean on that to say that Z77 is fine for dual GPU setups (it's claiming that "A is equal to B because we tested A against A with a gimicky workaround to mimic B").

I hope the OP has gotten enough out of this debate to help him or her make an informed decision.

It would be very helpful if someone at Tom's could put the PCIe bandwidth debate to rest by testing straight Z77 against straight X79 with no PLX or other gimics, and test one-, two-, three-, and possibly four-card setups at 1080p, 1440p, 1600p, and 3x 1080p resolutions in BF3 and other power-hungry games. I know how unlikely that would be, however, because it would require four 680s or 7970s. :(
 

Mozart25

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Many thanks for the link. I'm a bit curious how they achieved the following:



I was not aware it had 64 PCIe lanes...

Here's a comparison of four-way SLI in BF3 and Heaven at PCIe 2.0 and 3.0, each at 16x/8x/8x/8x:

http://www.overclock.net/t/1220962/vegas-heavyweight-display-and-computer-edition-2012/370#post_16915399
 

iiDeadSeriousii

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Yes, thank you I HAVE gotten a tremendous amount out of this debate. I am torn between the two chipsets because as you said Mozart, the CPU prices ARE the same (I forgot to edit my original post showing that they were both indeed $230).

It's just the quality of the boards and the value of the boards for x79 becomes a little more spotty. The midrange (150-200) for the Z77 is extremely competitive and there are GREAT values to be had there. Whereas X79 the best I can find STARTS at $219 for that ASRock Extreme 6.


I think I may start leaning towards the Z77 build based on the quality of boards that can be had for far less. On the X79 side I have to start considering $300+ boards to get the features and reliability I'd get out of a $160 Z77 board.

I'm with you Mozart, though I can try and gather the best I can for my setup, some of these benchmarks aren't helping out too well. They are comparing x16/x16 PCI 2.0 vs 3.0 directly instead of x16/x16 PCIe 3.0 vs x8/x8 3.0 which is exactly what I'd need. I still got about a week or two before I make it final but I'm probably around 60-40 for the Z77 build. The PLX bandaid has always struck me as a little questionable, especially since part of the limitations of an 1155 socket ARE the bus lanes as opposed to X79.

But you did not answer my other question, will the eventual IvyBridge-E be released on the current 2011 socket or a whole new one? When I try to research this all I get are the Haswell results.

EDIT: One last thing, any recommendations for an X79 mobo? Something preferrably comparable to the MSI GD65 I'm considering for my Z77 build.
 

Mozart25

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I can't help you out there. Anything out there is currently rumor or "RUMINT". It is expected that IB-E will be compatible with LGA 2011, but no word on if a new chipset will come out with it. Will Thunderbolt be included? More USB3 and SATA 3 ports? Will the same shitty heatspreader that Intel hobbled Ivy Bridge with be included with IB-E? Who knows at this point.

Haswell (LGA 1150, replacement to Ivy Bridge 1155), is coming out June 2. Ivy Bridge-Extended comes out sometime in the third quarter of this year (July - September).

I'd agree that Z77 is the more mature chipset at this point, and the OC Formula and equivalent boards are a fantastic value.

X79 boards:
Asrock X79 Extreme3 (4 ram slots) - $190: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157287
Asrock X79 Extreme6 (8 ram slots) - $220: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157289
Gigabyte UD3 - $220 after rebate: http://www.newegg.com/Product/Product.aspx?Item=N82E16813128532
ASUS ASUS P9X79 LE - $240: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131855
Asrock Fatal1ty - $265: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157288
Asus Rampage IV - $370: http://www.newegg.com/Product/Product.aspx?Item=N82E16813131808

That pretty much runs the gamut. Sure there are boards more expensive than the Rampage IV, but it pretty much represents the max value you would get out of a top-end board.

If I bought tomorrow, it'd probably be a Gigabyte UD3 or UP4.