BlueSmoke - Review : AMD Sempron 3400+

 Date  : Nov 16th, 2005
 Category  : CPU
 Manufacturer   : AMD
 Author  : Jin-Wei Tioh
AMD admittedly caught us a little off-guard when they launched the Sempron 3400+. Like most enthusiasts, we were keeping our eye on the higher end of microprocessor development, principally the migration to multiple cores such as in the Athlon64 X2, Xbox 360 and PS3.

To be fair, there hasn't been all that much activity since the inception of the Sempron line in June 2004, which was segmented into Socket A and Socket 754 products. The Socket A variants are based on the older K7 architecture, topping out at 3000+ and have faded into relative obsolescence.

On the other hand, the Socket 754 variants are based on the K8 architecture, eschewing some of the less important features of their full-blooded Athlon64 brothers, namely x64, Cool 'n Quiet and dual-channel memory support. This was accompanied by a decrease in L2 cache size - straight from the Duron and Celeron playbook. The cache reduction (to 256KB) noticeably decreased performance, since the K8 architecture's integrated memory controller simply cannot reduce memory access latency to that of L2 cache SRAM levels. However, they remained extremely competitive products especially in the hands of enthusiasts, who often overclocked them to make up for the smaller cache size.

In April 2005, the Sempron 3300+ was launched based on the Palermo core. It was manufactured on AMD's new 90nm process and featured all the enhancements that made it into the Athlon64 Venice core - SSE3 support, memory controller enhancements and a lower operating voltage. So we now have a Sempron that runs cooler, finally supports the full feature-set of the Athlon64 and should be easier to overclock due to more core voltage headroom and a higher multiplier.

Heaven on earth? Unfortunately, no. The Sempron 3300+'s L2 cache was further reduced to 128KB. While non-cache intensive applications ran just fine, cache sensitive applications such as games suffered severely. Increasing clockspeed failed to improve performance, indicating that at least 256KB of L2 cache is required by the K8 architecture to function well.

The Sempron 3400+ effectively remedies this dilemma. Let's now introduce this new Socket 754 contender.

 

The Sempron 3400+ is essentially a Sempron 3300+ with the L2 cache restored to 256KB as shown below.

AMD Sempron 3400+
Marking SDA3400AIO3BX
Core Palermo (Rev E6)
Vcore 1.4V
Frequency 2.0GHz
Package 754-pin Organic u-PGA 
L2 Cache 256KB
Memory Support DDR400 (Single-channel)
HyperTransport Bus 800MHz
Process 90nm SOI
Transistors 63.5 million
Die Size 84mm^2
Power Dissipation 62W (Typical)
Max Temperature 69C
Additional Features x64, SSE3, NX-bit, Cool 'n Quiet
 

More astute readers will immediately note that the Sempron 3400+ is darned near a Newcastle-core based Athlon64 3000+. It is no coincidence that they are price similarly ($125 and $140 respectively). There is no doubt that the extra 256KB of L2 cache on the 3000+ will enable it to best the 3400+ at stock speeds. However, the 3000+ typically overclocks to only 2.2 - 2.3GHz with air cooling. Can the Sempron 3400+ do better? We'll let the following two screenshots and the subsequent performance figures to speak for themselves.

 

The Sempron 3400+ has talked the talk. Now let's see it walk the walk.

Platform Information
CPUs Sempron 3400+
Athlon64 3700+
Motherboard Abit NV8
Cooler Thermalright XP-90
Interface Material Arctic Silver II
Memory 2 x 1024MB Crucial DDR400 (3-3-3-8)
Hard Drive Seagate Barracuda 7200.7 120GB
Graphics Card Chaintech 6600GT PCI Express
Power Supply Vantec Ion 460W
Operating System WindowsXP Professional SP2
Video Driver Forceware 81.85

Overclocked stability was tested using memtest86+ and verified by multiple makeworld runs under FreeBSD 6.0-AMD64.

 

Let's first take a look at the synthetic benchmarks.

The Sempron 3400+ keeps up admirably with the Athlon64 3700+ when both are compared at stock speeds. Once overclocked however, the Sempron bests the Athlon64 and is neck-and-neck with the overclocked Athon64. Given the results, this would seem to indicate that 256KB of L2 cache is sufficient to sate the demands of most general applications.

 

Let's see how well the synthetic performance figures translate into actual application usage. The archiving test was performed on a large 1GB folder containing a random mix of small and large, compressible and incompressible files. The MP3 encoding test was performed using MediaMonkey 2.4 to encode the entire second disc of the Ghost in the Shell : Standalone Complex soundtrack at the Insane quality setting (320Kbps CBR). Finally, the DiVX encoding test was performed using Gordian Knot 0.28.8 and the DiVX Pro 5.2.1 CODEC to encode the intro sequence of a Ghost in the Shell : Standalone Complex episode.

The same trend as before is observed, with the Sempron 3400+ providing satisfactory performance at stock speed and darned near demolishing the competition once overclocked.

 

Gaming is one area where it has been shown where the more L2 cache the merrier. This is the reason why the Athlon64 FX was bar none the best gaming CPU when it was released together with the regular Athlon64. Thus, we would naturally expect the performance of the Sempron 3400+ to suffer. Is this how it really pans out?

Our gaming test suite has been updated considerably to include the latest batch of popular games. All tests were conducted at low resolutions to avoid having the GeForce 6600GT in the testbed result in the game being GPU limited. Quake 4 and Half-Life 2 were tested using timedemos recorded in-house. Far Cry was tested using the Regulator timedemo from Tech Report. Unreal Tournament 2004 was tested using the UMark botmatch tool with 16 bots. Grand Theft Auto : San Andreas was tested using FRAPS to record the average framerate during the playback of the intro sequence. Finally, Final Fantasy XI was tested using the official benchmark tool from Square-Enix.

Unfortunately, the Sempron's smaller cache size hurts its gaming performance as expected. While still offering competent performance, the overclocked Sempron 3400+ barely keeps up with the Athlon64 3700+ at stock speeds or loses to it.

 

3D and workstation applications are areas where the reduced memory access latency offered by K8 architecture processors should be the primary performance determining factor, given the large data sets involved. Does L2 cache size play as big a role in these applications as games?

To represent 3D application performance, we turned to Cinebench 2003, a free benchmarking tool for both Windows and Mac OSes based on the CINEMA 4D software. The tool is set to deliver accurate benchmarks by testing not only a computer's raw processing speed but also all other areas that affect system performance such as OpenGL, multithreading and multiprocessors. It includes render tasks that test the performance of up to 16 CPUs on the same computer as well as software-only shading tests and OpenGL shading tests on huge numbers of animated polygons.

As with the synthetic and general usage tests, the Sempron 3400+'s smaller cache size is not an overly detrimental and it serves up excellent performance, even managing an upstart by beating the overclocked Athlon64 3700+ in the rendering test.

 

For workstation performance, we turn to SPECviewperf 8.1. SPECviewperf is a collection of popular professional application traces compiled into a single set of benchmarks, including 3D Studio Max, CATIA, EnSight, Lightscape, Pro/ENGINEER, Solidworks and Unigraphics. SPEC has initiated some significant changes in version 8.1 including a general code clean-up, improved EnSight viewset and wider platform support.

Again we generally observe similar trends as before, although the L2 cache size seems to play a slightly more integral role in this test suite.

 

The Sempron line is specifically targeted at the value segment of the market. However, it would be a stretch to classify the Sempron 3400+ as low-end. First off, it's priced awful close to the junior members of the Athlon64 family ($125 vs. $140 for the Atlon64 3000+). Feature wise, thanks to the new 90nm Palermo core, the Sempron line is now endowed with the full feature set of their full-blooded brethren, including SSE3, x64, NX-bit and Cool 'n Quiet support.

From a performance standpoint, we've already seen that the Sempron 3400+ offers performance reminiscent of the Socket 754 and Socket 939 Athlon64 3000+. Once overclocked, it can go toe-to-toe with the Athlon64 3700+ (both at stock and overclocked speeds) in quite a few instances or at worst still remain competitive, which should garner the interest of enthusiasts. Most impressive considering the nearly $200 price delta.

For the more adventurous, the Palermo core has trickled down into the lower spectrum of the Sempron line, including the 3300+, 3000+, 2800+, 2600+ and 2500+. The lower multipliers would mean a much higher HTT frequency is required to achieve the same clockspeed as the 3400+ but the appeal of cost savings is the carrot at the end of the stick. A word of caution to enthusiasts is that while all the models should overclock equally well, the increase in clockspeed may be insufficient to compensate for the smaller 128KB L2 cache.

One often-quoted caveat is that the Semprons are Socket 754 processors and hence lack some of the beneficial technologies found on the Socket 939 platform - dual-channel memory, PCI Express support, etc. However, it has been shown that having dual-channel memory does little to improve the performance of the K8 architecture (~5%). The availability of newer features has also been mitigated by the introduction of nForce4-4x based motherboards, bringing PCI Express support. While these do not support dual-core processors, we doubt this will be a huge issue for the majority of end-users. The small savings on motherboards (~$15) is also welcome icing on the cake.

Overall, we'd be hard pressed to not recommend the Sempron 3400+, especially if it is coupled with a more recent Socket 754 motherboard and overclocked.



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