Jetway has had many interesting products in the last couple of years. Smaller players in the PC Market often have a hard time getting noticed, and we applaud Jetway for bringing some unique products to market as a means of shining the spotlight on the Jetway brand. When we first heard of the Jetway nForce4 SLI board with 3 x16 PCIe slots, we figured it was just another interesting twist from Jetway. However, the idea is such a good one that we really wanted to take a closer look.

The first SLI motherboards provided SLI capabilities with a Paddle card that was reversed to switch between single x16 video and dual x8 operation.

DFI reverse-engineered the paddle in their SLI design and came out with the very flexible, but cumbersome jumper solution for SLI switching.

Other manufacturers like Asus have recently brought out SLI boards that use more expensive auto-switching technology where SLI can be turned on or off in BIOS. The advantage is mechanical simplicity, but the disadvantage is that overclocking performance may be compromised with a smaller range of overclocking than the more commonly used paddles and jumpers.

Jetway did a very clever and elegant rethinking of SLI in the design of the 939GT4-SLI-G, which is the subject of this review. All of the competing SLI boards use at least two-slot spacing between the two x16 slots to allow for double-width cards like the NVIDIA 6800 Ultra. Jetway used this fact to create a fresh new approach.

Jetway mounts 3 x16 PCIe slots single-spaced on their 939GT4-SLI. The outer slots, colored green, are configured as x8 slots and can be combined in SLI mode using the included SLI bridge. The middle x16 slot, colored yellow, is a single x16 PCIe slot. For single video, you use the yellow x16 slot. For dual video or SLI, you use the green slots.

Jetway does not need a paddle card, or jumpers, or switches in this arrangement. The design is simplicity in itself. What's more, this board theoretically could be a better performer without the paddle, jumpers or switches that can limit overclocking performance.

Basic Features: Jetway 939GT4-SLI

Specification	Jetway 939GT4-SLI-G
CPU Interface	Socket 939 Athlon 64
Chipset	nForce4 SLI (single chip)
BUS Speeds	200 to 400MHz (in 1MHz increments)
PCI/AGP Speeds	Asynchronous (Fixed)
PCI Express	100 to 145MHz in 1MHz increments
Core Voltage	Auto, 1.10V to 1.55V in 0.025V increments (with 4000+) PLUS +50mv to +350mv in 50mv increments Highest vCore 1.90V
DRAM Voltage	Auto, 2.55V, 2.65V, 2.75V, 2.85V, 3.05V, 3.25V
Chipset Voltage	1.5V, 1.6V, 1.7V
Hyper Transport Ratios	Auto, 200 to 1000 in 1X (200) increments
LDT Bus Transfer	16/16, 16/8, 8/16, 8/8
LDT Voltage	1.25V, 1.35V
CPU Ratios	Auto, 4x to 25x in 1x increments
DRAM Speeds	Auto, DDR200, DDR266, DDR333, DDR400
Memory Command Rate	1T, 2T
Memory Slots	Four 184-pin DDR Dual-Channel Slots Unbuffered Memory to 4GB Total
Expansion Slots	1 x16 PCIe Slots 2 x8 PCIe Slots (SLI) 2 x1 PCIe 3 PCI Slots
Onboard SATA	4-Drive SATA 2 by nF4
Onboard IDE	Two Standard NVIDIA ATA133/100/66/33 (4 drives)
SATA/IDE RAID	4-Drive SATA 2 PLUS 4-Drive IDE (8 total) Can be combined in RAID 0, 1, 0+1
Onboard USB 2.0 IEEE-1394	10 USB 2.0 ports supported nF4 No FireWire ports
Onboard LAN	PCIe Gigabit Ethernet by Marvel 88E8053 PHY (Dual LAN on 939GT4-SLI-D)
Onboard Audio	7.1 AC'97 Digital Audio with Realtek ALC850 8-Channel codec with 6 UAJ audio jacks
Other Features	AMD Dual-Core (X2) Support
BIOS	Phoenix Award (6/08/05)

Jetway is not a huge motherboard company, and we often see the worst selection and range of BIOS adjustments from the smaller companies in the market. You can throw that notion out the window with the Jetway because it has an extremely complete and broad range of adjustments available in the Phoenix-Award BIOS. The 200-400 CPU Clock Speed adjustment range is extremely wide, and it is supplemented by a useful range of vCore adjustments to 1.90V and Memory Voltage adjustments to 3.25V.

We would like to see an even broader range of vDIMM to 3.5V or higher to support the high voltage memory from OCZ and Mushkin, but there are so few boards that offer adjustments to the 3.25V offered by Jetway that it is difficult to complain. Someone involved in the design of this board and BIOS truly understood what the AMD enthusiast is looking for, and they did a great job in delivering those options. Jetway also implements all the nF4 chipset features.

Click to enlarge.

We are usually evaluating a Tier One board when we praise layout, but the Jetway is just about perfect in layout. The 24-pin ATX connector and the 4-pin 12V are both on board edges where they belong. Also noteworthy is the fact that both the IDE and floppy connectors are located on the upper right edge of the board - exactly where they belong for best access. The board is such an excellent design that it really deserves a better manual. The one provided is barely adequate, but you can find what you are looking for with a little effort.

Many nForce4 boards place dual-channel memory side-by-side in their designs, making cooling of high-speed memory even more difficult. Jetway staggers dual-channel by making dual-channel the matching color slots. With 2 DIMMs, this gives more room for heat dissipation and cooling.

We were even more surprised to see diagnostic LEDs and momentary switches for on/off and reset on the Jetway 939GT4-SLI.

Heat sinks on the mosfets is another feature seen on boards designed for overclocking like the DFI nF4 SLI. Jetway went to the additional expense of placing sizable heat sinks on the mosfets. There are very few boards that provide these enthusiast level features, and we're pleased to report that this Jetway is one of them. Considering that the Jetway is selling for around $129 on the web, this is particularly noteworthy.

Overclocking: Jetway 939GT4-SLI

Front Side Bus Overclocking Testbed
Default Voltage
Processor:	Athlon 64 4000+ (2.4GHz, 1MB Cache)
CPU Voltage:	1.55V (default 1.50V)
Cooling:	Thermaltake Silent Boost K8 Heat sink/Fan
Power Supply:	OCZ Power Stream 520W
Memory:	OCZ PC3200 EL Platinum Rev. 2 (Samsung TCCD Memory Chips)
Hard Drive:	Seagate 120GB 7200RPM SATA 8MB Cache
Maximum OC: (Standard Ratio)	244x12 (4x HT, 2.5-3-3-7) 2928MHz (+22%)
Maximum FSB: (Lower Ratio)	314 x 9 (2563MHz) (3x HT) (2826MHz, 2 DIMMs in DC mode) (+57% Bus Overclock)

The Jetway is a very nicely laid out nForce 4 board with excellent adjustments, and we fully expected that we would be recommending the Jetway to those who run at stock or only modestly overclock. Well, our expectations were far too modest!! The Jetway turns out to be one of the best overclocking nForce4 boards that we have ever tested and moves right up there with the DFI SLI and Sapphire/ATI single video Innovation board.

The Jetway turned in one of the highest overclocks at the stock 12X multiplier that we have ever tested at 122% or a 244 CPU clock. Lowering HT to 3X, we also reached one of the highest overclocks that we have ever achieved at lower multipliers by hitting 314 at a 9 multiplier. What's more, the Jetway was exceptionally stable at both overclocks, handling Super Pi and other benchmarks with ease.

Getting to these stratospheric overclocks on air is not as easy as many may think. There are a number of design tricks that the best overclocking boards use to reach these high performance levels, which is why smaller companies often do quite poorly in overclocking. It takes design staff and attention to detail to create a great overclocker - resources that are usually in short supply at smaller companies. We don't know where Jetway purchased this design excellence, but we can tell you that the Jetway 939GT4-SLI is a dynamite overclocker - one of the best that we have tested. With a lower selling price, the Jetway gives AMD shoppers a new choice in an enthusiast-level board.

This brings us back to the earlier question of whether or not the dedicated slots with no paddles, jumpers, or switches might improve performance. It is clear that the Jetway performs very well in overclocking, and if this design is the reason, then others should copy the Jetway design.

Memory Stress Testing

Our memory stress test measures the ability of the Jetway nForce4 to operate at its officially supported memory frequency (400MHz DDR), at the lowest memory timings that OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. To make sure that memory performed properly in Dual-Channel mode, memory was only tested using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).

Stable DDR400 Timings - One Dual-Channel (2/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2
RAS to CAS Delay:	2T
RAS Precharge:	7T
Precharge Delay:	2T
Command Rate:	1T

Using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-7 timings at default voltage, which was the only memory voltage available.

Stable DDR400 Timings - 4 DIMMs (4/4 DIMMs populated)
Clock Speed:	200MHz
CAS Latency:	2.0
RAS to CAS Delay:	2T
RAS Precharge:	7T
Precharge Delay:	2T
Command Rate:	2T

Tests with all four DIMM slots populated on the Jetway 939GT4-SLI required a 2T Command Rate with 4 DIMMs in two dual channels. This is the pattern seen on every other top-performing Socket 939 board. This performance is completely competitive with the best that we have seen on nForce4 motherboards for Socket 939.

Test Setup

Performance Test Configuration
Processor(s):	AMD Athlon 64 4000+ (2.4GHz) Socket 939
RAM:	2 x 512MB OCZ PC3200 Platinum Rev. 2
Hard Drive(s):	Seagate 120GB 7200 RPM SATA (8MB Buffer)
Video AGP & IDE Bus Master Drivers:	NVIDIA nForce 6.66
Video Cards:	NVIDIA 6800 Ultra (PCIe) NVIDIA 6800 Ultra (AGP)
Video Drivers:	NVIDIA nForce 77.77
Operating System(s):	Windows XP Professional SP2 Direct X 9.0c
Motherboards:	Jetway 939GT4-SLI-G (nForce4) ULi AP9567A (M1695/M1567) Abit An8 Fatal1ty Biostar NF4UL-A9 Chaintech VNF4-Ultra DFI LANParty UT nF4 Ultra-D ECS KN1 Extreme Epox 9NPA+ Ultra Winfast NF4UK8AA (Foxconn) Asus A8N-SLI Deluxe DFI LANParty nF4 SLI-DR Gigabyte K8NXP-SLI MSI K8N neo4/SLI Platinum

Tests used OCZ PC3200 Platinum Rev. 2, which uses Samsung TCCD chips. All memory ran at 2-2-2-7 timing in all benchmarks.

The NVIDIA 6800 Ultra was used for testing both PCIe and AGP performance on the ULi board. The 6800 Ultra video cards were tested at the same video timings and differed only in interface - AGP or PCIe. Resolution in all benchmarks is 1280x1024x32 unless otherwise noted.

All single and dual GPU benchmarks were run with a matched pair of NVIDIA 6800 Ultra reference cards, identified as Rev. A04. All game benchmarks, both single video and SLI, were run in 1600x1200 video mode with 4X Anti-Aliasing and 8X Anisotropic filtering enabled. The exception is Aquamark 3, which uses a standardized 1024x768 setup to generate comparable benchmark results.

Results for the Jetway 939GT4-SLI are color-coded in red in all graphs. Results for the other boards are in blue.

General Performance & Encoding

The Jetway is certainly competitive with the best NVIDIA nForce4 boards that we have tested. Performance is at or near the top in Business Winstone, Multimedia Content Creation, PCMark04, and PCMark05. Add to that, the top score for the Jetway in AutoGK Media Encoding and the general performance has to be considered among the best 939 boards that we have tested.

Overclocking Comparison

Jetway has produced a very balanced design in the 939GT4-SLI, and it clearly shows in the overclocking performance of this board. This is particularly clear in comparing the overclocking performance of the Jetway to other tested Socket 939 boards.

Gaming Performance

Doom 3

Aquamark3

Unreal Tournament 2004

Far Cry

Half-Life 2

Gaming, in both single video and SLI, is at or near the top of our performance charts in every gaming benchmark. This certainly lends credibility to the theory that the simpler PCIe slot arrangement on the Jetway is likely contributing to lower overhead and better performance.

Our Take

Surprises are one of the things that can turn the routine of testing computer components into a few moments of excitement. We confess that we were totally surprised to find the Jetway at least the equal of any enthusiast AMD 939 board that we have tested. Who would have even considered before this review that the Jetway 939GT4-SLI-G would benchmark in the same league as the top 939 boards that we have tested, and overclock in the same league as the legendary DFI LANParty nF4 SLI. But benchmarks are benchmarks and the Jetway equaled the best Socket 939 boards we have tested, and then went on to top performance in stock ratio overclocking and reduced ratio overclocking.

There is a lot to like about the Jetway 939GT4-SLI, starting with a near ideal board layout. There is also the elegant simplicity of the 3 PCIe video slots with a dedicated x16 single video slot and an additional pair of x8 Dual/SLI video slots. The 3 slots are not overkill or a waste of board space, since even the most basic SLI board uses 3 slot spaces for the SLI video slots. The Jetway uses the same space, but the 3 dedicated slots do away with any need at all for paddles, jumpers, or switches for SLI. This simplicity probably contributes to the excellent performance that we found with the Jetway in these tests.

Add to this: processor voltages to 1.9V, memory voltage to 3.25V, a wide 200 to 400 range for CPU clock, and a complete range of memory adjustments and chipset/LDT voltages, and you have the legitimate makings of an AMD enthusiast board. The diagnostic LEDs and momentary switches are just the icing on the enthusiast cake. We've seen other boards all decked out with everything but performance, but that is certainly not the case with this Jetway - it performed as well in all our tests as we hoped that it would. Our only real complaint is that the tested BIOS did not implement the added memory ratios (433, 466, 500, 533) available with the Rev. E Athlon64 processors. However, we have asked Jetway for an updated BIOS to fix this oversight.

Some will be screaming and flaming with our recommendation here, but at a $129 web price, you should really include this Jetway on your short shopping list for Socket 939 AMD enthusiast motherboards. This Jetway delivers great value and performs very well, no matter how you measure the performance. It's nice to see a real surprise once in a while, and this Jetway will open the eyes of any buyer who approaches it with an open mind.

A great job, Jetway, and we hope that you can really get behind this board with the kind of support that it deserves. We highly recommend the 939GT4-SLI to both the non-overclocking AMD user and the AMD Enthusiast looking to reach new heights in overclocking with their new Athlon 64.