Nvidia nForce 650i SLI Chipset and only $130: ASUS P5N-E SLI Mainboard Review

Together with the expensive nForce 680i SLI chipset Nvidia started shipping better value core logic sets for Intel Core 2 processors. Today we are going to review one of the first mainboards on nForce 650i SLI designed by ASUS.

by Ilya Gavrichenkov
03/09/2007 | 10:48 AM

Nvidia’s entry into the market of chipsets for Intel Core 2 family processors was not exactly a success. Granted, the Nvidia nForce 680i SLI has no rivals in terms of formal characteristics as its capabilities surpass Intel’s, let alone AMD’s, alternatives, but the specification alone does not mean everything nowadays. Neither of the off-the-shelf mainboards based on the nForce 680i SLI that we’ve checked out in our labs so far has avoided our criticism. The products on the reference design (for details see our Nvidia nForce 680i SLI Chipset Review) and the ASUS Striker Extreme all have innumerable small problems that can spoil a fastidious user’s impression from the mainboard. And what is especially discouraging, mainboards on the top-end chipset from Nvidia are indecently expensive. That’s the main reason why the nForce 680i SLI cannot be expected to achieve universal popularity. The Intel P965 is still the most demanded chipset for desktop Core 2 systems.


This situation can change soon, though, as Nvidia has began shipping its new nForce 650i SLI chipset, a cheaper version of the expensive nForce 680i SLI. First mainboards on the new chipset have already appeared in shops at prices comparable to mainboards based on Intel’s chipsets. Considering the characteristics of the nForce 680i SLI, we can expect the new mainboards to have a very appealing functionality/price ratio. In this review we will discuss the ASUS P5N-E SLI mainboard, one of the first products on the Nvidia nForce 650i SLI chipset.

But before we scrutinize this promising solution, we have to say a few words about the Nvidia nForce 650i SLI chipset itself as its positioning in the midrange price sector obviously implies some functional limitations. You can see them right away in the flowchart.

As you see, the main difference of the Nvidia nForce 650i SLI from the more advanced 680i SLI is that it has fewer PCI Express lanes, which affects the implementation of SLI technology. The nForce 680i SLI has a total of 46 PCI Express lanes, but the nForce 650i SLI has only 18. As a result, the senior version of the chipset implements SLI technology as PCI Express x16 + x16 and additionally offers a PCI Express x8 bus for a physics accelerator whereas the nForce 650i SLI supports SLI as PCI Express x8 + x8 and doesn’t offer any additional bus for a physics accelerator. It is easy to explain. Although the nForce 680i SLI and nForce 650i SLI are based on the same North Bridge chip (C55 SPP), they have absolutely different South Bridges. The South Bridge of the nForce 650i SLI chipset is far less functional and this is not limited to its having fewer PCI Express lanes.

Particularly, the nForce 650i SLI has only one Gigabit Ethernet controller instead of the senior chipset’s two, four instead of six Serial ATA-300 ports, and eight instead of ten USB 2.0 ports. On the other hand, the nForce 650i SLI offers two Parallel ATA-133 channels which is not a common thing for a modern chipset to have. It doesn’t seem strange, though, when you learn that the South Bridge of the nForce 650i SLI is nothing else but the nForce 430 MCP, which has been long known to us by the integrated nForce 6150 chipset. Nvidia knows the art of unification perfectly!

Besides the above-mentioned things, some capabilities of the nForce 650i SLI are disabled on the mainboard BIOS level. Thus, although it uses the same North Bridge as the nForce 680i SLI does, the cheaper chipset lacks official support for Nvidia LinkBoost technology and for high-speed memory with EPP. These limitations can hardly matter for experienced users who prefer to configure their systems manually, though.

Now, let us put everything together:

So, the Nvidia nForce 650i SLI chipset seems to be able to become a foundation of a full-featured system if you don’t care that it doesn’t support SLI according to the PCI Express x16 + x16 design. And it can surely be viewed as a strong opponent to the Intel P965.

Specification and Accessories

Here’s the first mainboard on the nForce 650i SLI chipset that we’ve got – ASUS P5N-E SLI.

The question is if the ASUS P5N-E SLI mainboard, based on the highly promising nForce 650i SLI chipset, can be regarded as equal to popular iP965-based solutions. The answer becomes clear even from its specification.



LGA775 processors: Celeron D, Pentium 4, Pentium D,
Pentium 4 XE, Pentium XE, Core 2 Duo, Core 2 Quad
and Core 2 Extreme


NVIDIA nForce 650i SLI (C55 SPP + nForce 430 MCP)

FSB frequencies

133-750MHz (with 1MHz increment)


Adjustable Vcore, Vmem, North Bridge voltage.
Independently adjustable PCI and PCI Express bus frequency.
EPP technology support.


4 DDR2 DIMM slots for dual-channel
DDR2-1067/800/667/533 SDRAM

PCI Express x16 slots

2 (with NVIDIA SLI support in 8x + 8x mode)

PCI Express x1 slots


PCI expansion slots


USB 2.0 ports

8 (4 – on the rear panel)

IEEE1394 ports

2 IEEE1394a ports
(1 – on the rear panel, by VIA VT6308P controller)


2 ATA-133 channels (in the chipset)

Serial ATA

4 Serial ATA-300 channels (by the chipset, with RAID support)
1 eSATA channel
(on the rear panel, by the JMicron JMB360 controller)

ATA RAID support

RAID 0, 1, 0+1, 5 in the chipset

Integrated sound

6-channel HD codec: Realtek ALC883

Integrated LAN

Gigabit Ethernet (in the chipset)

Additional features



Phoenix AwardBIOS v6.00PG


ATX, 305mm x 229mm

Yes, it can. In its main formal parameters this mainboard is not inferior to most iP965-based products. Yet we should keep it in mind that the ASUS P5N-E SLI is inexpensive whereas top-end products like the ASUS Commando belong to a higher class (for details see our review called Asus Commando: First Look at a Dream Mainboard). As we are examining the mainboard, we’ll see a lot of instances of the engineers having tried to minimize the product cost to make it more affordable. Thus, this mainboard’s competitiveness should be evaluated basing on its price which is currently $120-140.

Take the packaging and accessories, for example. You see the economy at once. The mainboard comes in a moderate-size plain box without pretty pictures or translucent windows or even a handle to carry it.


It is somewhat empty inside. Besides the mainboard, the box contains a user manual, a CD with software and drivers, an I/O shield for the back panel of your system case, cables for your floppy drive and Parallel ATA devices, two Serial ATA cables and an appropriate power adapter. These necessities are complemented with only three extra things: a bracket with a couple of USB ports, a flexible cable to connect graphics cards in SLI mode, and a set of exclusive connectors called Q-Connector.

On the other hand, we can’t seriously criticize this set of accessories. Although it is indeed scanty in comparison with more expensive mainboards from ASUS, there is in fact everything necessary to use the mainboard.


The mainboard’s functionality is just like its accessories. It offers everything necessary but without any extras. Most of the features of the ASUS P5N-E SLI are implemented through the employed chipset.

The mainboard supports a full range of LGA775 processors, including dual-core and quad-core CPUs from the Core 2 series. Moreover, we have no doubt the mainboard is ready for the upcoming CPUs with a 1333MHz FSB despite the lack of an official announcement. We are sure it supports such CPUs because of the mainboard’s overclocking results and because it uses the C55 SPP (in the nForce 680i SLI chipset this North Bridge supports the upcoming FSB officially).

So, we don’t see any reason why the ASUS P5N-E SLI cannot be used with the upcoming CPUs.

The ASUS P5N-E SLI doesn’t differ much from the ASUS Striker Extreme, for example, when it comes to working with memory. The C55 SPP allows setting the frequency of DDR2 SDRAM with divisors relative to the FSB frequency (there are not so many divisors available, though: 1:2, 5:8, 3:4 and 1:1 FSB:DRAM) as well as quasi-asynchronously. In the quasi-asynchronous mode the mainboard’s BIOS Setup allows entering any memory frequency value from 400 to 2600MHz, but the real frequency is set up by using an appropriate divisor selected from the extended set available in the asynchronous mode.

Although Nvidia promised some limitations concerning EPP technology in the nForce 650i SLI chipset, the ASUS P5N-E SLI supports EPP without any problems.

The mainboard’s two PCI Express x16 slots allow uniting a pair of installed graphics cards into a single graphics subsystem. In SLI mode both slots work as PCI Express x8. If only one graphics card is installed, the first slot works as PCI Express x16 and the second is disabled. The operation mode of the graphical slots is selected in an old and primitive way, by means of a switch card.

Thanks to the nForce 430 South Bridge, the ASUS P5N-E SLI mainboard has eight USB 2.0 ports, four SATA-300 ports (with support for 3Gbps data-transfer rates, NCQ and RAID), two Parallel ATA-133 channels, and a Gigabit Ethernet port.

These features are complemented by means of a VIA VT6308P controller that provides two IEEE1394 ports and a JMicron JMB360 chip that provides an additional external eSATA port (ASUS calls it SATA On-the-Go ).

The ASUS P5N-E SLI mainboard offers six-channel sound through a HD codec Realtek ALC833. Although this is an eight-channel codec, only six channels are wired on the mainboard. This codec is an inexpensive solution and its support for EAX 2.0 is inferior to codecs from Analog Devices that ASUS installs on its more expensive mainboards.

PCB Design

The ASUS P5N-E SLI didn’t impress us with its accessories or specification. Everything is just what you can expect from a midrange product. But when it comes to PCB design, the mainboard turns to have very remarkable and unusual traits.

First of all, there is a gigantic aluminum heatsink on the chipset’s North Bridge:

This heatsink is indicative of the developer’s desire to minimize the product cost, although an active copper cooler would have been more appropriate here because the C55 chip is very hot at work. The aluminum heatsink becomes as hot as to raise our apprehensions about the health of the North Bridge. So, we recommend replacing this cheap heatsink with something more efficient, especially if you are going to overclock your system or if there is no strong airflow around the North Bridge in your system case.

There is no heatsink at all on the South Bridge, but this chip is not so threateningly hot. However, there are mounting holes in the mainboard around the chip so that you could take care about its cooling, too.

The questionable economy on heatsinks is not limited to the chipset pieces. The CPU voltage regulator (it has a classic three-channel design on the ASUS P5N-E SLI) lacks any cooling, either. This circuit doesn’t include digital feedback or SMT capacitors, which is expectable considering the mainboard’s price. The regulator is based on ordinary electrolytic capacitors manufactured by United Chemi-Con which are reliable, though.

The elements of the CPU voltage regulator, including capacitors, are located on the PCB right around the CPU socket, which is not good. They may prevent you from installing a cooler with a massive base (the North Bridge heatsink may be an obstacle, too).

You can also find it difficult to connect the additional 12V power cable. The mainboard has a 4-pin connector, and the modern 8-pin connector doesn’t plug into it easily due to the jumper indiscreetly placed nearby.

There are a few other flaws in the PCB design of the ASUS P5N-E SLI many of which can be seen in the picture.

The FDD slot is placed very inconveniently behind the last PCI. The placement of the SATA ports is not good, either. You may find it difficult to use them if you’ve got two graphics cards in your system. The inappropriate choice of places for the various slots may be explained by the reduced area of the PCB (to make it cheaper), but what we can’t explain and justify is that the mainboard offers only three fan connectors. That’s not enough for a mainboard of that class that carries a lot of hot elements on board.

The mainboard’s rear panel seems somewhat empty. It offers PS/2 ports for the mouse and keyboard, four USB ports, one IEEE1394 port, a LAN port (RJ-45) with diagnostic LEDs, an eSATA port, three analog audio connectors, a coaxial SPDIF output, and a parallel port.

There are headers on the PCB to connect four more USB ports, an IEEE1394 port, and a COM port.


A mainboard’s overclockability is largely determined by its BIOS. The ASUS P5N-E SLI being based on the same North Bridge as the ASUS Striker Extreme, we might expect similar CPU and memory overclocking options if it were not for the developer who deliberately limited the number of BIOS Setup options of the inexpensive nForce 650i SLI-based mainboard. Hopefully, this won’t affect the mainboard’s overclockability much.

Go to the Advanced menu to find options pertaining to configuring and overclocking memory and CPU. Most of the options an overclocker might be interested in are in the JumperFree Configuration section.

Here you can disable EPP technology and access BIOS Setup pages with voltage and frequency settings.

The System Clocks subsection contains only one option, the frequency of the PCI Express bus that can be varied from 100 to 131MHz stepping 1MHz.

The Voltage Control section provides access to three voltages:

The frequency of the FSB and the memory bus is specified in the FSB & Memory Config section.

Note that the FSB frequency is specified in an unusual quad pumped format. In ordinary terms, the FSB can be clocked at frequencies from 133 to 750MHz. The memory frequency is set up relative to the FSB (using FSB:DRAM divisors of 1:2, 5:8, 3:4 and 1:1) or pseudo-asynchronously. The nForce 650i SLI doesn’t have a truly asynchronous clock generator to clock the memory bus. When you select the desired value in BIOS Setup, the mainboard will pick up a most appropriate divisor (the chipset offers more than enough of them) and will report the actual memory frequency. In most cases this frequency is no less than 10-20MHz lower than the desired one. In the pseudo-asynchronous mode the memory frequency can be selected from a range of 400MHz to 2600MHz on the ASUS P5N-E SLI mainboard.

The CPU Configuration section allows choosing the CPU frequency multiplier (for CPUs that allow changing their multiplier) and provides access to various CPU-related technologies.

All memory-related settings can be found in the Memory Timings Settings subsection of the Chipset section.

As you can see, the mainboard gives you control over all the basic memory subsystem timings and over the Command Rate parameter.

By the way, almost all of the mentioned CPU and memory parameters and voltages can be set at Auto, which simplifies the configuration process.

Besides the overclocking-related options, the mainboard’s BIOS Setup offers a couple of extra features. First, it allows saving profiles with settings into flash memory or even in files. Second, it incorporates the EZ Flash 2 utility that allows updating BIOS without leaving BIOS Setup.

The program can take files with new BIOS versions from a floppy, a CD, a hard disk formatted in FAT, and from USB flash drives.

The mainboard’s hardware monitoring options are limited to showing three fan speeds and the temperatures of the CPU and mainboard.

The BIOS features the traditional Q-Fan technology that can vary the speed of the fans depending on temperatures.


The description of the mainboard’s BIOS Setup shows that the ASUS P5N-E SLI is not as settings-rich as many other overclocker-friendly mainboards are, but it does allow to change all the main parameters. Hopefully, it can make a good platform for overclocking, too.

Furthermore, mainboards for power users that we have discussed lately on our site have very sophisticated BIOS Setup programs you can spend hours in, trying to find optimal settings. The ASUS P5N-E SLI is a relief in this respect. It offers two frequencies and three voltages, just what you need to overclock your CPU. Of course, you can hardly hope to set any overclocking records with such scanty settings, but anyway.

To check out the mainboard at overclocking, we took an Intel Core 2 Extreme X6800 processor, 2GB of DDR2 SDRAM (Corsair TWIN2X2048-8500C5D), a PowerColor X1900 XTX 512MB graphics card, and a Western Digital Raptor WD1500AHFD hard disk drive. Using the mainboard’s quasi-asynchronous memory mode, we made the memory modules work at a frequency of 800MHz or a little lower with 4-4-4-12-1T timings throughout our tests. The CPU was cooled with a Zalman CNPS-9500LED cooler and we also installed a 60mm fan on the North Bridge heatsink. The stability of the system was verified by running the ORTHOS program, which was based on Prime95 code.

We soon found the highest FSB frequency the mainboard was stable at. Just like in our tests of the ASUS Striker Extreme, it was 490MHz.

To achieve this result we had to increase the North Bridge voltage to 1.563V and the CPU voltage to 1.475V. It seems simple, but it is not. It’s been a long time since ASUS made its last mainboard on which all overclocking options worked well without any reservations.

First, we achieved such a high FSB frequency only after installing a fan on the North Bridge heatsink. Without that fan, the mainboard would freeze during the POST even at 450MHz FSB.

Second, tests suggest that there’s little sense in high FSB frequencies on the ASUS P5N-E SLI as well as on the ASUS Striker Extreme. The FSB strap is changed somewhere within the 400-450MHz range and leads to a catastrophic hit of memory performance, which is not always made up for well by the CPU frequency growth.

Third, we encountered a FSB hole with our ASUS P5N-E SLI. The mainboard was totally inoperable at FSB frequencies from 400 to 450MHz.

Besides that, the P5N-E SLI sets the voltages too low, which is typical of ASUS mainboards. Particularly, the real CPU voltage proves to be about 0.05V lower than the value you set in BIOS Setup. It also bottoms out by about 0.05V more at high CPU loads, which is within the Intel specifications, but irritates overclockers.

The quasi-asynchronous clocking of memory by the nForce 650i SLI chipset allows overclocking DDR2 SDRAM independently from the FSB on the discussed mainboard. We tried to find the highest frequency for our TWIN2X2048-8500C5D modules at 2.4V voltage, but were somewhat disappointed. The ASUS P5N-E SLI proved to overclock DDR2 SDRAM worse than the Striker Extreme had done. The maximum memory frequency we achieved was 550MHz.

On the ASUS Striker Extreme these very modules had worked at 587MHz. Still, we have some hope for improvements in the future versions of the mainboard’s BIOS. We used version 0401 which was already much better in that respect than the previous versions, indicating that ASUS was still working on the mainboard.


The ASUS P5N-E SLI mainboard we’ve been talking about is based on the Nvidia nForce 650i SLI chipset we haven’t met with before, so it is interesting to know how this mainboard performs in its regular mode. We will compare its performance with that of other popular mainboards on widespread chipsets from AMD, Intel and Nvidia.

We will use the following hardware for the test:

We try to put the mainboards under identical conditions, so system memory works at 400MHz with 4-4-4-12 timings in every case. The memory controller settings differ in one parameter, though, which is the Command Rate. Mainboards on Intel’s chipsets do not allow changing this setting due to chipset limitations. That’s why the i975X- and iP965-based platforms work at 2T Command Rate.

The tests show that the ASUS P5N-E SLI is just a little slower than the ASUS Striker Extreme, a product from a higher class. So, we have no complaints about performance of the reviewed mainboard. On the other hand, you shouldn’t forget that the ASUS P5N-E SLI implements SLI mode in a cut-down variant, using PCI Express x8 buses. It means that this mainboard is going to be slower in SLI mode than the ASUS Striker Extreme which supports full-featured SLI. The difference in performance may amount to 20% in the most advanced of today’s gaming applications.


The ASUS P5N-E SLI is not free from drawbacks some of which are not to be disregarded, yet this very mainboard makes us confident that the Nvidia nForce 650i SLI chipset, which is the foundation of it, is an excellent basis for midrange Core 2 systems.

Talking about the particular mainboard on this chipset, the ASUS P5N-E SLI can make a good alternative to popular iP965-based products. This mainboard provides satisfactory functionality, good performance, and acceptable overclocking opportunities for its price category ($120-140). Moreover, it allows using graphics cards with Nvidia’s GPUs in SLI mode, even through at a lower speed than you would have with the more expensive nForce 680i SLI-based mainboards.

Well, we do not want to overpraise this mainboard. We haven’t yet tested nForce 650i SLI-based products from other manufacturers and the ASUS mainboard may not look so great against them. It does have a number of flaws after all.