1. Motherboard

The backbone of every computer. The type of mobo determines the processors and video cards that we will have available to make the rest of our choices, mainly the processor and graphics card. Having said that, every time a new component is favored the whole decision tree needs to be adjusted. I believe that this is the best place to start.

The x16 PCI Express Graphics

Depending on the chipset some x16 PCI Express slots can run at x8 or even x4 speed when SLI/CF mode is enabled. This is very bad news as the descriptions can be confusing. I the reviews that follow, I have noted what the true speed of all the available graphics slots are. For a successful SLI/CF configuration, two x16 PCIe modes should be present.

As a deterrent I have added a list of the incurred penalties for using x4 and x8 PCIe slots. Makes me wonder why x4/x8 still exist at all in current motherboards. (The following are Quake 4 accumulated fps)

Video Card PCI fps
HD2900 XT (512 MB) PCIe 1.0a x4
PCIe 1.0a x8
PCIe 1.0a x16
1209.4 (-32.7%)
1673.6 (-6.9%)
1796.8
8800 GTS (512 MB) OC PCIe 1.0a x4
PCIe 1.0a x8
PCIe 1.0a x16
1678.1 (-24.9%)
2063.6 (-7.7%)
2235.3
Nvidia and ATi cards both suffer severe penalties when used in anything other that a x16 slot.

The New PCI 2.0 Interface

For completion, we must look into the capabilities of PCI 2.0 motherboards. Current video cards seem to lack the correct engineering to take advantage of the faster bus, as benchmarks show that PCI 1.0 and PCI 2.0 cards perform the same at the moment (only 0.9% difference).

Toms Hardware : Less Than 1% Average Performance Gain At FSB1333 Vs. FSB1066.

I doubt that PCI 2.0 will mature for at least another year or so, therefore I can leave those mobos out of the selection tree. In any case only a handfull of graphics cards, namely the Nvidia’s Geforce 8800 GT/GTS 512 MB and ATI’s Radeon HD3850 /3870 are already equipped with the PCI Express 2.0 interface.

The guys over at Toms Hardware have a definitive article on this subject that you can read below. It is crystal clear that my video card must run on a pure x16 PCIe slot and that investing in PCI 2.0 is not worth it at the moment.

Tom’s Hardware : Crossfire Meets PCI Express 2.0

SLI/CrossFire in x8 and x16 PCIe interfaces

I would like my motherboard to have support for dual video cards, but its not a necessity. Even if I decide not to buy two right now, I would like the option of adding an extra one later when the prices drop. The performance gain has been shown to be around 35-50% and not 100% as might be expected, which is equivalent to a video card upgrade in some cases. The following table shows some of the performance bonuses that one might expect.

Video Card PCI fps (accumulated)
HD2900 XT (512 MB)
(Crossfire mode)
PCIe 1.0a x8 x8
PCIe 2.0 x16 x16
1190.1 (-10.9%)
1335.1
HD3850 (256 MB) OC (Crossfire mode)
PCIe 1.0a x8 x8
PCIe 2.0 x16 x16
981.4 (-13.0%)
1128.6
HD3870 (512 MB) OC
(Crossfire mode)
PCIe 1.0a x8 x8
PCIe 2.0 x16 x16
1163.8 (-11.3%)
1312.8
Here both PCIe 1.0 and 2.0 are compared, alongside the effect of x8 and x16 slots.

In all honesty it would have been best to compare PCIe 1.0a x16x16 and PCIe 2.0 x16x16 performance in this graph, but having clearly established from the Tommy article I mention above that PCI 1.0a=PCI 2.0, I thought it more interesting to show how the technology has matured.

For right now, I want to concentrate on selecting a class of motherboard, which means I must decide on the chipset, CPU support and if I want SLI or CrossFire. This is akin to deciding if I want to go with nVidia or ATi cards which is of course a pretty big deal. Choice of mobo is akin to picking a video card, and does not restrict my decision on CPU at this stage. My research shows that selecting a motherboard does not restrict my decision on processor, as the indistry has several combinations of motherboard chipsets and CPU support.

Lets have a more detailed look at the two video chipsets now.

SLI with nVidia

SLI is available only to PCI Express cards and you need to have a motherboard with two x16 PCI Express slots and the motherboard must be based on an nVidia chipset.

SLI Motherboard Chipsets PCI Express Mode
nForce 780i SLI x3 Two PCI Express 2.0 x16, One PCI Express 1.0 x16
nForce 780a SLI x3 One PCI Express 2.0 x16, Two PCI Express 1.0 x8
nForce 750i SLI
nForce 750a SLI
Two PCI Express 2.0 x8
nForce 680i SLI x3 Two PCI Express 1.0 x16, One PCI Express 1.0 x8
nForce 680i LT SLI
nForce4 SLI X16
nForce Professional 3600 and 3050
nForce Professional 2200 and 2050
Two PCI Express 1.0 x16
nForce 590 SLI x4 Two PCI Express 1.0 x16
nForce 650i SLI
nForce 570 SLI
nForce 570 LT SLI
nForce 560 SLI
nForce 500 SLI
nForce4 SLI
nForce4 SLI XE
nForce Professional 3600
nForce Professional 3400
nForce Professional 2200
Two PCI Express 1.0 x8

The first true option here is the nForce 590 SLI, that has two real x16 PCI slots, which means that if/when SLI is used both of the cards will run at x16 PCI speeds. The 650i SLI is outdated now, and its x8 PCIe slots are simply a turn off, thus the 680i SLI chipset is the strongest contender here.

CrossFire with ATi

CrossFire is available only to PCI Express cards and you need to have a motherboard with two x16 PCI Express slots and the motherboard must be based on an AMD/ATI or Intel chipset.

Crossfire Motherboard Chipsets PCI Express Mode
AMD 790FX
Two PCI Express 2.0 x16 with two video cards
One PCI Express 2.0 x16 and two x8 with three video cards
Four PCI Express 2.0 x8 with four video cards
Intel X38 Two PCI Express 2.0 x 16, One PCI Express 1.0 x4
AMD 790X Two PCI Express 2.0 x16
AMD 580X (ATI CrossFireXpress 3200) Two PCI Express 1.0 x16
AMD 570X One PCI Express 1.0 x16, One PCI Express 1.0 x8
Intel 975X Two PCI Express 1.0 x8, One PCI Express 1.0 x4
AMD 480X (ATI CrossFireXpress 1600)
ATI Radeon Xpress 200 "CrossFire Edition"
Two PCI Express 1.0 x8
Intel P35
Intel G33
Intel P965
Intel 945P
One PCI Express 1.0 x16, One PCI Express 1.0 x4

Favorites

I have determined that I am not interested in SLI at this moment, or PCI 2.0 interface tecnhology. So I can pick any kind of processor and graphics card without worrying about any further details. These are my favorites so far:

Intel 680i LT SLI: The 680i and 680i LT have cought my eye on performace board reviews and setups, with the definite advantage of having two full x16 PCIe slots for the best SLI action. Turns out the 680i LT SLI offers almost all of the overclocking facilities that the 680i SLI has, short of some cap in max CPU and memory voltages. It also costs about $50 less than its bigger brother, so thats always good too. See these Legit Reviews and Digit-Life articles for details.

eVGA 680i LT SLI Motherboard : $170

  • Active cooling on mobo chips, that ideally need replacing with better heatsinks and silent fans.
  • ECC memory supported (passes timing information to motherboard)
  • CPU Core 1.6V max (from 1.8V) and CPU FSB 1.4V max (from 1.5V)
  • Tested with Intel Core 2 Duo E6300 1.86GHz ($171.99)O/C to 3.37GHz, 1.4625V on water.

Intel P35: The Intel P35 chips are very popular, despite the single x16 PCIe slot, as the boards often come loaded with overclocking features. There are several models and a wide array of features to choose from. In addition, I often see these used as reference boards when comparing new CPUs as towards their overclockability, something very promising. The G33s are exactly the same as the P35s, but with the inclusion of an Intel IGP.

MY CHOICE: Foxconn MARS LGA 775 Intel P35: $175 from ZipZoomFly

  • Copper chipset heatsinks, with optional fan
  • FSB 1333/1066MHz, RAID, Audio, LAN
  • Gladiator BIOS, very stable overclocking features
  • Chipset overclocking guide by Shamino himself available from Foxconn website (northbridge, southbridge, memory controller,etc)
  • I believe that this is one of the highest quality P35 motherboard on the market today.

AMD 570X: Going up, it seems easy to shrug past the selection tree here, because AMDs are loosing the speed race to Intel at the moment. However, their pricing is extremely competitive. I would like to note the AMD 570X chipsets at this point and the rock solid customer reviews that boards such as the ASUS M2N-SLI Deluxe have received. Paired with a top of the line AMD X2 6000+ processor, this board has a lot of power for less.

ASUS M2N-SLI Deluxe AM2 NVIDIA nForce 570 SLI: ($130)

  • Used on Tom’s CPU 2007 test rig for AMD processors, for AM2 socket processors
  • Passive mobo chip cooling
  • Excellent reviews from 1200 buyers, crappy on-board audio that would need replacing
  • Simple installation and excellent hardware combatibility
  • Great O/C abilities
  • Paired with AMD Athlon 64 X2 6000+ ($160) is excellent performer (PCMark 6158) (OC?)

Other: Asrock is a spinoff company from ASUS. They are cheap and have very good performance results as reported by many users and definately worth a look. Recommended for budget builds.

Notes

High End

  • Foxconn MARS P35 ($230) : This mother was designed by DFI engineers to be the highest quality overclocker and stable motherboard. Used by Shamino (the overclocking champion of the world) to achieve 30K 3dMark06 Score. Nice!
  • DFI P35-T2R ($240): High end P35 motherboard. Expensive but full featured.

Medium

  • ASUS P5K-E/WIFI-AP ($150) : Pushes the E6750’s PCMark CPU test from 6873@2.13GHz to 10658@4.16GHz [Setup]. Has FSB1333 for future CPUs. Fast memory and cooling needed.
  • ABIT IP35 Pro ($175): Leading Abit motherboard with extreme overclocking features, that comes highly recommended from the community.

Budget

  • Gigabyte P35-DS3L ($90) : Several versions exist: DS3R has RAID SATA support, DS3P has RAID SATA and SLI support, for $30-$60 more. Used by the THG guys to overclock the legendary Pentium D 805 1.8GHz to 4.1GHz with watercooling.
  • ABIT IP35-E ($90) : Very good OC capabilities through Abit BIOS, onboard Audio/LAN, no RAID.

Key Reviews

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