|Introduction And Specifications|
Energy efficiency and power consumption are major concerns for modern computing architectures, whether you're an Enthusiast, an IT Manager in a Data Center, or simply an ecologically minded individual. Let's face it, the modern high end computer is like a small space heater for all intents and purposes, and where there's heat, there's power consumption -- typically a lot of power consumption.
Both AMD and Intel have made great technological strides when it comes to power consumption in their current CPU architectures. Both the Athlon 64 X2 and Core 2 Duo processor cores have elaborate clock gating schemes to allow their cores to ramp down during periods of inactivity or light workloads.
AMD's line of "Energy Efficient Processors" takes this approach one step further by allowing operating input voltages to dip even further down, well below the standard range of the first Athlon 64 X2 and FX dual core chips that hit the market. This approach not only reduces power consumption and heat output in their low-power "Cool-n-Quiet" mode, but also during full throttle active usage scenarios.
Lower Power Consumption:
Energy Efficient models available at 65 Watts max power:
Energy Efficient models available at 35 Watts max power:
NOTE: The third digit of a desktop processor's part number details the maximum power consumption of that model.
|Test Systems, Vital Signs And Temperatures|
Below are our systems specs for the various configurations we tested. Next we'll step through some initial voltage and temperature measurements we with these new energy efficient Athlon 64 X2 chips.
A quick scan in CPU-Z shows just what voltages and clock speeds the two new chips are running at in our test system.
CPU-Z Processor Details - Athlon 64 X2 3800+ And 4600+
Here we see the Athlon 64 3800+ EE clocking in at 2GHz and a svelte 1.02v, while the 4600+ EE show 2.4GHz at 1.184v. Incidentally, these tests were run with AMD "Cool-n-Quiet" disabled to show the processors in their full-speed state. Next we'll show you what Cool-n-Quiet clock gating looks like under no-load conditions.
Temperature And Voltage Monitor - No Load
Both the Energy Efficient Athlon 64 3800+ and Athlon 64 4600+ drop down to 1GHz speeds when Cool-n-Quiet is enabled and there is no load on the CPU. Notice the 4600+ drops its voltage down to about 1v as well, like the 3800+
Temperature And Voltage Monitor - Full Load
At full clock speed and 100% load the new Energy Efficient Athlon 64s show impressive thermal characteristics. The 3800+ still oscillates around the 1v threshold at its core and the 4600+ has now ramped up to 1.15v according to Asus' PC Probe utility. Let's graph the temps for you here and compare them to similar architectures.
Please keep in mind that these core CPU temperatures were recorded on an open air bench test with ambient room temp of about 20oC or 68oF. Processor core temperatures would likely ramp higher in closed chassis environments. Regardless, fully loaded, the new energy efficient Athlon's show excellent thermal characteristics. Incidentally, we tested with a stock all copper Athlon 64 X2 cooler, though AMD supplied us with a lower profile aluminum/copper hybrid cooler, since these lower operating temp ranges require much less exotic cooling solutions.
|Power Consumption And Overclocking|
Please keep in mind that we were testing total system power consumption here at the outlet, not just the power being drawn by the processors alone. In this test, we're showing you a ramp-up of power from idle on the desktop to full CPU load and then a ramp to full CPU and Graphics load. We tested with a combination of Prime 95 and Folding@Home on running on each test system to create 100% CPU load.
We've tested the processors and compared them to a number of different system configurations here, so there are few observation that can and should be made. First take note of the motherboards we listed in brackets next to each processor. Note that the GeForce 6150/nForce 430 chipset-based system consists of a mini-ATX motherboard with a single PCI Express graphics slot. This is in significant contrast to the fully loaded nForce 590 SLI and Intel 975X-based motherboards we tested. We should point out that the 16 extra PCI Express lanes alone could account for up to 2-3 watts of extra power draw if they were all in use, though we did test with only a single GeForce 7900 GTX in all test systems.
So in short, the reason we're providing measurements for the Athlon 64 5000+ here, on both platforms, is to illustrate the effect the motherboard has on the numbers were showing in the rest of the graphs. If you tack on an additional 5-10 watts for the 6150/nF430-based systems, that will give you an idea of how the new Athlon 64 X2 4600+ and 3800+ Energy Efficient cores perform in a higher-end system board.
The EE 3800+ sneaked in under the wire at 119 Watts full load and the 4600+ wiggled in just under 150 Watts. At idle there is only a 9 watt differential between the two chips and they are easily the lowest power consumption of the group. For applications like HTPCs and other small form factor installations, these low power dual core Athlons will provide a bit more breathing room for the significantly smaller Power Supplies that are typically incorporated into these types of systems.
Of course with their low power and heat characteristics, the new Athlon 64 4600+ and 3800+ were sure to be decent overclockers, so we turned up the dials a bit to see where these processors would take us.
Overclocking At Default Voltage
At default voltages we were able to remain stable with a 15% increase in core speed on the 3800+ and a 10% increase on the 4600+. With a voltage boost .10v above standard Athlon 64 X2 ranges, the 3800+ hits a stable 2.6GHz and the 4600+ hits 2.8GHz. It goes without saying but your mileage may vary of course. Still at 2.8GHz you're looking at A64 FX-62 speeds on the 4600+ and 5000+ level speeds for the 3800+ at 2.6GHz.
PCMark05 gives us a quick snap-shot of general computing workloads, usage models and how each processor we tested fares against each other.
"The CPU test suite is a collection of tests that are run to isolate the performance of the CPU. The CPU Test Suite also includes multithreading: two of the test scenarios are run multithreaded; the other including two simultaneous tests and the other running four tests simultaneously. The remaining six tests are run single threaded. Operations include, File Compression/Decompression, Encryption/Decryption, Image Decompression, and Audio Compression" - Courtesy FutureMark Corp.
Not surprisingly, this multi-threaded benchmark shows each processor in proper scale relative to its clock speed and architecture. The Core 2 Duo E6700 edges out the Pentium Extreme Edition 965 while the rest of the Athlon 64 team brings up the rear in sequence according to their respective clock speeds.
"The Memory test suite is a collection of tests that isolate the performance of the memory subsystem. The memory subsystem consists of various devices on the PC. This includes the main memory, the CPU internal cache (known as the L1 cache) and the external cache (known as the L2 cache). As it is difficult to find applications that only stress the memory, we explicitly developed a set of tests geared for this purpose. The tests are written in C++ and assembly. They include: Reading data blocks from memory, Writing data blocks to memory performing copy operations on data blocks, random access to data items and latency testing." - Courtesy FutureMark Corp.
More of the same here in this simple raw memory bandwidth test of PCMark05. It is surprising how much of a lead the Core 2 Duo system has over its counterpart in this test, which is indicative of the enhancements Intel made to its on-chip caching subsystem.
|Microsoft Office And Nero Burning ROM|
Below we have the results from WB 5's Office XP SP2 and Photoshop 7 modules, recorded in seconds. Lower times indicate better performance here, so the shorter the bar the better.
Standard Office type applications show the field tightly packed within a few seconds of each other, save for the E6700. The significantly cooler and quieter Athlon 64 X2 4600+ actually manages to edge out the high-end nuclear reactor driven Pentium Extreme Edition 965. OK, perhaps nuclear is over the top. Hydro-electric maybe then?
It almost hurts to look at the score the Core 2 Duo E6700 put up in our Nero Burning ROM CD encoding test. The chip serves up a sound thrashing almost halving the second fastest score put forth by the Pentium Extreme Edition 965. Once again the Athlons bring up the rear here though with numbers that fall in line with each other relative to their clock speeds. On the other hand, If we were able to come up with some sort of performance per watt equation to easily illustrate these result, the final outcome may surprising. If you recall from our power and core temperature tests, these new Energy Efficient CPUs do consume considerably less power.
The WorldBench 5 Photoshop 7 benchmark module is next. Other than Nero and perhaps Office XP, Photoshop is probably one of the more popular applications for our readership so we place a bit more stock in these numbers.
The Core 2 Duo once again reins supreme by a long shot, a full minute plus faster than the A64 X2 5K+. However the 4600+ puts up a real nice showing against the Pentium EE 965 and as we illustrated earlier, it does so with dramatically less power draw and radiated heat.
|Lame MP3 Multi-Threaded|
In our custom LAME MT MP3 encoding test, we convert a large WAV file to the MP3 format, which is a very popular scenario that many end users work with on a day-to-day basis to provide portability and storage of their digital audio content.
In this test, we created our own 223MB WAV file (a never-ending Grateful Dead jam) and converted it to the MP3 format using the multi-thread capable LAME MT application in single and multi-thread modes. Processing times are recorded below. Once again, shorter times equate to better performance.
The results of our custom LAME MT MP3 encoding benchmark, whether in its single- or multi-threaded mode, tell essentially the same story as the Photoshop 7 benchmark on the previous page. The Core 2 Duo E6700, Pentium Extreme Edition 965, and the A64 X2 5000+ were all able to complete the encoding process faster than the low-power Athlons, but they do so because they are clocked higher and consumer more power. Try to run one of those CPUs at the lower voltages the 4600+ and 3800+ require, and they may not even remain stable.
|Cinebench 3D Rendering|
The Cinebench 2003 benchmark is an OpenGL 3D rendering performance test, based on the commercially available Cinema 4D.
This is a multi-threaded, multi-processor aware benchmark that renders a single 3D scene and tracks the length of the entire process. The time it took each test system to render the entire scene is represented in the graph below (listed in seconds).
This is one of our personal favorite benchmark modules here at HH, because the results generated are so very linear and very much indicative of raw computational throughput. Traditionally, the Athlon 64 X2 architecture has done very well with this test and in multi-threaded mode, the 4600+ and 3800+ EE processors put up some very respectable numbers. Also, once again the Core 2 Duo is in a class by itself, and it's even more underscored in single-threaded performance. Regardless, when you consider the power efficiencies of the 4600+ here, its showing against the Pentium 965 is impressive.
|3DMark06 And Quake 4|
3DMark06's built-in CPU test is a multi-threaded "gaming related" DirectX metric that's useful for comparing relative performance between similarly equipped systems.
This test consists of two different 3D scenes that are generated with a software renderer which is dependent on the host CPU's performance. This means that the calculations normally reserved for your 3D accelerator are instead sent to the central processor. The number of frames generated per second in each test are used to determine the final score.
3DMark06 lines things up according to rank and serial number here. There's no real insight to gain except the scale of where this benchmark scores each processor. For our money here the sweet spot is probably the $300ish A64 5000+ or the Core 2 Duo but you'll pay nearly double for that currently and they're on back order as of this publication date.
For our next game test, we benchmarked all of the test systems using a custom single-player Quake 4 timedemo. Here, we installed the game's official v1.2 patch which is SMP capable, tuned the resolution down to 640x480, and configured the game to run at its "Low-Quality" graphics setting. Although Quake 4 typically taxes today's high-end GPUs, when it's configured at these minimal settings, it too is more CPU and memory-bound than anything else.
Quake 4 heavily favors the memory bandwidth and throughput of the Core 2 Duo architecture in this test, but beyond that, it's a real horse race. After the Core 2 Duo, our money is on the 4600+ Energy Efficient CPU with a $240 MSRP for full retail PIB (processor in a box) kits.
|Performance Analysis And The Final Word|
Benchmark And Performance Summary:
From a power consumption and heat profile perspective, these new Energy Efficient Athlon 64s offered some of the lowest draw characteristics we've seen in a long time. Even under 100% CPU load the highest clock speed 4600+ CPU never broke 40oC in our open air bench test.
Pricing for the new Energy Efficient Athlon 64 X2 series of product will roll out accordingly:
*65Watt TDP - **35watt TDP
We don't have pricing in yet for the SSF variant of the 3800+ but that was in fact the version of the processor we tested in this article. As you can see the EE varieties carry about a 10-15% premium. When all is said and done it's nice to have a bit more selection from AMD targeted toward lower power consumption and better thermal characteristics. Either one of the processors we showed you today would make for excellent choices in a Home Theater PC setup or other Small Form Factor configuration.
Essentially these processors are a re-characterization of the current Athlon 64 X2 but at lower operating voltages and with lower profile thermal solutions required. There's no question, clock for clock the Core 2 Duo has one up on the Athlon 64 X2 right now but AMD is making every effort to "sell what they have" and they're still trying to bring a value-add approach to their current processor line-up.