Shuttle SN27P2 SFF: AM2 gets the Tiny Treatment
by Jarred Walton on June 30, 2006 11:00 PM EST- Posted in
- Systems
Overclocking
While overclocking and SFF systems are rarely a great match, we did test the limits of the SN27P2 in this area. Here are our results.
The initial BIOS we received with the system did not have working CPU multipliers, which severely limited our overclocking attempts when using an Athlon X2 5000+ processor. The maximum HyperTransport bus speed is 300 MHz, but if you're stuck with a 13X multiplier you'll never get there. In fact, given that the 5000+ is near the top of AMD's current dual core chips, it should come as little surprise that we were not able to overclock more than 10% without difficulties. Even at such a small overclock, with the added voltage required for stability, noise levels when the CPU was placed under a full load were substantially higher.
Our recommendation is that if you plan on getting a dual core processor, don't plan on major overclocks -- not that we really expect most people to overclock small form factor systems, but it is worth mentioning. It appears that the cooling system simply isn't capable of dealing with the heat output generated from most overclocked X2 chips, though we did test the system briefly with an FX-62 and found that it worked without difficulty at stock speeds.
We got around the BIOS multiplier limitations by installing an Athlon 64 3000+ (default clock speed of 1.8 GHz). With the lower 9X multiplier and a single CPU core, we were able to overclock to 2.7 GHz, reaching the maximum supported bus speed. Unlike many of the AM2 motherboards we've tested, however, this was only possible by dropping the HyperTransport multiplier down to 3X. In this area, overclocking was similar to what we saw on the nForce4 platform: the HyperTransport bus really didn't want to run much over 1000 MHz, but given that the HTT bus is rarely a bottleneck in terms of system performance this isn't a major concern.
If for whatever reason you are interested in buying a cheap single core Athlon 64 and putting it in the SN27P2, it appears that the system is more than capable of overclocking such a processor. On the other hand, if you want to purchase a dual core processor, either don't plan on overclocking much, or purchase an X2 3800+ and plan on topping out at around 2.6 GHz (with a noisier system than if you were to simply buy a 5000+). It could also be that the forthcoming low-power X2 chips will overclock better and/or run quieter in this type of system, but as we have not been able to get a hold of any of these we cannot say for certain.
Memory Stress Testing
The overclocking features present on the SN27P2 are a bit more limited than what we see with many high-end motherboards, and CPU voltage tops out at 1.525V. Perhaps more importantly, the DDR2 memory voltage tops out at 2.0V. Our Corsair memory is rated at PC2-8500 with 5-5-5-18 timings, but we have been able to run this memory at DDR2-800 with 3-3-3-9 timings on several other motherboards when using 2.2-2.3V. We were able to run with 4-4-4-12 timings with the RAM set to 2.0V, but we could not drop the CAS/tRP/tRCD values to 3.0 (individually or together) with the limited voltage options.
The BIOS also only offers the standard memory timing adjustments (CAS/tRCD/tRP/tRAS), which further limits our ability to tweak for maximum performance. This may result in slightly lower performance relative to the top AM2 motherboards, but for the most part the differences should be minor and not something you would notice during actual use (without running benchmarks). If you are truly concerned about memory performance, your best bet is to purchase some PC2-6400 memory that is designed to run with low latencies at lower voltages (1.8-2.0V). That type of memory may or may not overclock as much as the Corsair memory we are using, but as we just demonstrated, overclocking really shouldn't be your primary concern with the SN27P2 - or any SFF computer, for that matter.
Testing with all four DIMM slots populated stresses the memory subsystem more, but as you can see we were still able to maintain 4-4-4-12 timings. Running with 4GB of memory (or more) is really only beneficial if you are running a 64-bit operating system, however, and for the time being we continue to prefer XP over XP x64. Let's not even talk about Windows Vista x64 Beta 2 performance. However, in another year we expect 4GB configurations to become far more common.
While overclocking and SFF systems are rarely a great match, we did test the limits of the SN27P2 in this area. Here are our results.
| Shuttle SN27P2 Overclocking | |
| Processor: | Athlon X2 5000+ (AM2) |
| Chipset: | nForce 570 Ultra |
| CPU Voltage: | 1.400V (1.300V default) |
| Memory Settings: | 5-5-5-15 2T DDR2-800 Setting |
| DDR2 Results: | 13 x 215HTT = DDR2-798 |
| HT Multiplier: | 4x above 200HTT |
| Memory Voltage: | 2.0V |
| Chipset Voltage: | 1.65V |
| Maximum CPU Overclock: | 13 x 215 = 2795 MHz |
| Shuttle SN27P2 Overclocking | |
| Processor: | Athlon 64 3000+ (AM2) |
| Chipset: | nForce 570 Ultra |
| CPU Voltage: | 1.525V (1.300V default) |
| Memory Settings: | 4-4-4-13 2T DDR2-400 |
| DDR2 Results: | 9 x 300HTT = DDR2-600 |
| HT Multiplier: | 4x above 210HTT, 3X above 260 HTT |
| Memory Voltage: | 2.0V |
| Chipset Voltage: | 1.70V |
| Maximum CPU Overclock: | 9 x 300 = 2700 MHz |
| Maximum HTT Overclock: | 300 MHz (50%) - BIOS maximum |
The initial BIOS we received with the system did not have working CPU multipliers, which severely limited our overclocking attempts when using an Athlon X2 5000+ processor. The maximum HyperTransport bus speed is 300 MHz, but if you're stuck with a 13X multiplier you'll never get there. In fact, given that the 5000+ is near the top of AMD's current dual core chips, it should come as little surprise that we were not able to overclock more than 10% without difficulties. Even at such a small overclock, with the added voltage required for stability, noise levels when the CPU was placed under a full load were substantially higher.
Our recommendation is that if you plan on getting a dual core processor, don't plan on major overclocks -- not that we really expect most people to overclock small form factor systems, but it is worth mentioning. It appears that the cooling system simply isn't capable of dealing with the heat output generated from most overclocked X2 chips, though we did test the system briefly with an FX-62 and found that it worked without difficulty at stock speeds.
We got around the BIOS multiplier limitations by installing an Athlon 64 3000+ (default clock speed of 1.8 GHz). With the lower 9X multiplier and a single CPU core, we were able to overclock to 2.7 GHz, reaching the maximum supported bus speed. Unlike many of the AM2 motherboards we've tested, however, this was only possible by dropping the HyperTransport multiplier down to 3X. In this area, overclocking was similar to what we saw on the nForce4 platform: the HyperTransport bus really didn't want to run much over 1000 MHz, but given that the HTT bus is rarely a bottleneck in terms of system performance this isn't a major concern.
If for whatever reason you are interested in buying a cheap single core Athlon 64 and putting it in the SN27P2, it appears that the system is more than capable of overclocking such a processor. On the other hand, if you want to purchase a dual core processor, either don't plan on overclocking much, or purchase an X2 3800+ and plan on topping out at around 2.6 GHz (with a noisier system than if you were to simply buy a 5000+). It could also be that the forthcoming low-power X2 chips will overclock better and/or run quieter in this type of system, but as we have not been able to get a hold of any of these we cannot say for certain.
Memory Stress Testing
| Shuttle XPC SN27P2 Stable DDR2-800 Timings - 2 or 4 DIMMs 2 or 4 slots populated - 1 or 2 Dual-Channel Bank(s) |
|
| HTT Clock Speed: | 200MHz |
| Timing Mode: | 800MHz |
| CAS Latency: | 4 |
| RAS to CAS Delay: | 4 |
| RAS Precharge: | 4 |
| RAS Cycle Time: | 13 |
| Command Rate: | 2T |
| Voltage: | 2.0V |
The overclocking features present on the SN27P2 are a bit more limited than what we see with many high-end motherboards, and CPU voltage tops out at 1.525V. Perhaps more importantly, the DDR2 memory voltage tops out at 2.0V. Our Corsair memory is rated at PC2-8500 with 5-5-5-18 timings, but we have been able to run this memory at DDR2-800 with 3-3-3-9 timings on several other motherboards when using 2.2-2.3V. We were able to run with 4-4-4-12 timings with the RAM set to 2.0V, but we could not drop the CAS/tRP/tRCD values to 3.0 (individually or together) with the limited voltage options.
The BIOS also only offers the standard memory timing adjustments (CAS/tRCD/tRP/tRAS), which further limits our ability to tweak for maximum performance. This may result in slightly lower performance relative to the top AM2 motherboards, but for the most part the differences should be minor and not something you would notice during actual use (without running benchmarks). If you are truly concerned about memory performance, your best bet is to purchase some PC2-6400 memory that is designed to run with low latencies at lower voltages (1.8-2.0V). That type of memory may or may not overclock as much as the Corsair memory we are using, but as we just demonstrated, overclocking really shouldn't be your primary concern with the SN27P2 - or any SFF computer, for that matter.
Testing with all four DIMM slots populated stresses the memory subsystem more, but as you can see we were still able to maintain 4-4-4-12 timings. Running with 4GB of memory (or more) is really only beneficial if you are running a 64-bit operating system, however, and for the time being we continue to prefer XP over XP x64. Let's not even talk about Windows Vista x64 Beta 2 performance. However, in another year we expect 4GB configurations to become far more common.
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Calin - Monday, July 3, 2006 - link
Most any ATX case will be quiter and possibly cooler inside than one of those SFF computers. However, they will be twice as big (or more). If that's ok with you, that's great - ATX all the way. If not, a laptop or a SFF certainly makes sense (even if the price is much better on the full ATX front).JarredWalton - Monday, July 3, 2006 - link
I don't know - it depends on the ATX case you're talking about and how many fans you want to install. If you install two or three case fans (or more) and they aren't temperature controlled, a lot of the less expensive ATX cases will be louder than many SFF cases. Lower quality power supplies will also make a lot of noise. If you don't want a big case, and you are interested in getting an extremely easy to set up bare-bones system, SFF computers are really very nice.I do wish prices were about $100 lower, however. $300 for a SFF I can justify; $400+ is a lot more difficult to stomach. For that much money, you can get a good power supply, motherboard, and pretty much any case that you want. I suppose part of it has to do with economies of scale; I don't know how many SFF cases Shuttle has sold, but I doubt they sell as many SFFs someone like ASUS would sell motherboards. That means all of their R&D costs that go into creating a smaller case have to be passed on as a larger percentage of the price.
JarredWalton - Saturday, July 1, 2006 - link
There was no opinion given on which CPU to choose, was there? I simply stated (and this is the expanded version) that even if you're going to buy AMD anyway and couldn't care less about Core 2 Duo, AMD has price cuts scheduled for July 24th so you can pick up an X2 CPU for a lot less than current prices. Here's my opinion:Core 2 Duo will be faster than anything AMD has to offer at least in the short term. AMD X2 will cost less at most (all?) price points, and in some cases (gaming), you're probably GPU limited either way since the current maximum for an SFF is going to be the 7950 GX2. I expect Shuttle will have the SD37P2 out some time after C2D launches, but since they're already 1 month behind the AM2 launch and you still can't purchase the SN27P2, that trend will likely continue and the SD37P2 won't be available until probably early September or so. (I could very well be wrong on that account, but I'm simply going by recent history.)
Which is the better choice? As you have so clearly demonstrated, that's a matter of personal taste. Some people are only going to buy AMD at present; others will only buy Intel. Most would like to buy whichever offers the best performance at a specific price point. I would guess that AMD will be competitive in the price/performance area even if C2D is faster overall, so in the end they get what they're happy with. I still wouldn't purchase an AM2 chip until those price cuts take affect.
VooDooAddict - Saturday, July 1, 2006 - link
Simply.
Will the 7950 Fit?
Does the BIOS support the card?
Can the powersupply keep it running with 2 gigs of RAM and a AMD 5000+?
As soon as I saw the 7950 anouncement all I could think about was building a new SFF system around it.
JarredWalton - Saturday, July 1, 2006 - link
I don't have one available, but my understanding is just about any motherboard with an X16 slot will work with the 7950 GX2. Since I managed to install a 7900 GTX in the SN37P2, I'm pretty sure the GX2 is actually a bit smaller overall, so it will certainly fit. Is it compatible? Well, the SN27P2 uses an NVIDIA chipset, so if it's *not* compatible, NVIDIA has a serious problem with support of GX2. In other words, I'm 99% certain that it will work.VooDooAddict - Monday, July 3, 2006 - link
I didn't think the issue was the chipset ... I thought it was the BIOS.JarredWalton - Monday, July 3, 2006 - link
Right, the BIOS needs to support non-graphics devices in the X16 slots. My point is that if a board using NVIDIA's chipset doesn't support NVIDIA's top GPU, what's the chance of getting everyone else to support it?