by Ilya Gavrichenkov
10/11/2005 | 05:45 PM
There recently have been more DDR2 SDRAM related articles in the Memory section of our site, and quite appropriately so. The fact is the DDR1 SDRAM memory type just ceased to progress. JEDEC didn’t ratify any new standards since PC3200 and the manufacturers of overclocker-targeted modules do not focus much on improving the characteristics of their DDR1 products due to several reasons.
Firstly, no progress in modules is possible without appropriate DDR1 chips and the chip makers haven’t yet offered anything better than the widely popular Samsung TCCD and Winbond UTT chips whose potential is already nearly exhausted. And no advances are expected in this area since the chip makers have long switched to the newer, DDR2 type of SDRAM. Secondly, there is not much practical sense in getting higher than DDR600 because you have to overclock you entire system to enable this memory frequency which is not always possible. For example, you have to increase the clock-gen frequency from the default 200MHz to 300MHz to use DDR600 SDRAM in an AMD Athlon 64 computer. To do such overclocking, you need an overclocker-friendly mainboard and, in most cases, the option of reducing the CPU frequency multiplier below its default value. We must acknowledge that the recently released Athlon 64 processors on the Venice and San Diego cores allow using step-up memory frequency divisors which make it possible to use modules faster than DDR600, but such divisors must still be supported in the mainboard’s BIOS.
And anyway, a good idea can never die. Not so long ago we spotted overclocker-friendly memory modules with a fantastic marking of PC5600, i.e. DDR700 SDRAM! The modules come from PDP Systems, the owner of the Patriot Memory brand. The release of DDR1 SDRAM modules that surpass many DDR2 SDRAM ones in speed provoked much enthusiasm among the overclocking community most of whom stick to the DDR1-based Athlon 64 platform.
We just could not remain indifferent, either. So, we got a sample of the product and will now try to check its properties in this review. The main question we are obsessed with among others is how did the manufacturer manage to build a much faster memory module than the competing products out of the same memory chips?
The DDR700 SDRAM memory kit from Patriot Memory we are about to test looks like follows:
The fancifully shaped plastic package contains two DDR SDRAM modules, 512MB each. So, this dual-channel memory kit gives you one gigabyte of memory in total. The model number on the sticker of each module reads “PDC1G5600ELK”.
This is how the marking is spelled out:
Total kit capacity – 1GB
PC5600 – DDR700 SDRAM
Eased Latency – non-aggressive timings
Besides the marking and the barcode, the sticker tells you the total capacity of the dual-channel kit and mentions the module’s ability to work as PC5600 DDR SDRAM with 3-5-5-9 timings. We’ll talk yet about the timings and other characteristics below. Right now let’s have a closer look at the heat-spreaders these modules are equipped with:
Patriot Memory used a new type of heat-spreaders in their new PC5600 modules – no other maker of overclocker-friendly SDRAM modules has such heat-spreaders. What’s so original about them? The heat-dissipation area is increased here by means of 13 ribs, about 0.7mm in height. The manufacturer claims that the original shape of the heat-spreaders makes them 5-7% colder, despite their being made of ordinary aluminum. This factor, of course, improves the overclockability of the modules, but can hardly be a decisive factor in their reaching the 700MHz mark.
The heat-spreaders are colored red, the typical color of all DDR1 SDRAM modules from Patriot Memory. Among decorations you can note the embossed and mirrored Patriot logotype on one side of a module and the abbreviation DDR on the other. Combined with the red color of the PCB, this gives the Patriot PDC1G5600ELK kit a most appealing look.
The heat-spreaders are fastened to the chips with sticky thermal tape which didn’t allow us to remove them and check the type of the employed memory chips. Judging by numerous indirect signs, however, we can say that Patriot PDC1G5600ELK modules are based on Samsung TCCD chips which have earned a good reputation among overclockers (and there just seems to be no other candidates on the market to challenge the 700MHz height).
The official specification of Patriot Memory PDC1G5600ELK modules can be obtained at the manufacturer’s website :
The specification betrays how Patriot made its modules stable at 700MHz. The trick is in the obviously slack timings and in the Command Rate parameter increased to 2T. We want to remind you that the DDR SDRAM manufacturers haven’t yet dared to increase RAS# to CAS# Delay and RAS# Precharge to 5 cycles – such latencies are typical for DDR2 SDRAM rather. The higher Command Rate also negatively affects the performance of an Athlon 64 system, as a rule.
Well, we’ll have some performance tests shortly, but we want to note another stipulation made in the documentation on the modules. It says that this product is tested for compliancy with its specification on mainboards from the DFI LANParty UT NF4 series. The manufacturer doesn’t guarantee Patriot PDC1G5600ELK to work on other mainboards at 700MHz frequency. They act wisely here since only highest-quality overclocker-targeted platforms are capable of stable operation at 350MHz clock-gen frequency (i.e. when the memory is clocked at 700MHz).
In a nutshell, there’s nothing extraordinary about Patriot PDC1G5600ELK modules. PDP Systems “invented” a marketing product to impress a sensitive overclocker. The manufacturer didn’t have to do much to put the DDR700 tag on the product and this memory doesn’t have any advantages except its high rated frequency (and theoretical bandwidth).
Let’s see what is written into the modules’ SPD.
The SPD information is rather strange. There are two sets of parameters here: DDR606 with 2.5-5-5-11 timings and DDR714 with 3-6-6-13 timings. We don’t pretend to understand the reasons for the engineers to program the modules’ SPD this way but these parameters should allow you to start up your computer and enter the BIOS to correct the settings on almost any Athlon 64 mainboard. As for booting the OS up, our DFI LANParty UT NF4 Ultra-D mainboard couldn’t boot Windows XP until we manually configured the latencies and DIMM voltage.
As we said in the previous section, the reviewed Patriot PDC1G5600ELK modules combine an extremely high frequency with very bad timings. As a result, their operation in the default mode may not be so profitable from the overall system performance standpoint. On the other hand, this memory is based on Samsung TCCD chips which can be characterized as universal. Besides supporting high frequencies, they do very well at frequencies about 400-500MHz with aggressive timings. Viewed from this perspective, the modules may prove a good product if you do not focus on frequency alone.
To see how Patriot PDC1G5600ELK memory behaves at different timings, we assembled a testbed out of the following hardware parts:
The goal of this test was to find the highest frequencies the Patriot PDC1G5600ELK modules would be capable of working at with different timings. The stability of the system was questioned by running Memtest86+ version 1.60 and then S&M 1.7.3 (in Windows XP). This two-tier approach ensures the highest credibility of the results.
We tested our Patriot PDC1G5600ELK modules at the default voltage of these chips, i.e. 2.9V. It is in fact useless to increase the DIMM voltage any higher for modules based on Samsung TCCD chips – this doesn’t improve their overclockability.
Against the specification, we set the Command Rate parameter at 1T as overclockers will likely to prefer this value.
As you can see, the results are quite typical for TCCD-based memory modules. The Patriot PDC1G5600ELK could work at 446MHz with aggressive 2-2-2-10 timings and at 500MHz with 2-3-3-10 timings. When we slackened the timings to 3-4-4-12, the product of Patriot Memory reached 588MHz frequency.
Advanced memory modules from other manufacturers, based on the same chips, can boast more impressive results in terms of operational frequencies. For example, the OCZ EL DDR PC-4800 Dual Channel Platinum modules of DDR600 SDRAM can work at frequencies up to 640MHz with 3-4-4-12 timings (for details see our article called DDR600 SDRAM Tested: OCZ EL DDR PC-4800 Dual Channel Platinum Review ). The Patriot PDC1G5600ELK memory, however, behaved typically well for modules based on Samsung TCCD chips at the aggressive timings. Higher frequencies with aggressive timings are supported by modules on Winbond UTT chips, for example by OCZ EL DDR PC3500 Gold GX.
But where is the promised 700MHz? Yes, there’s nothing like that frequency in the diagram above. It seems we can’t do without setting the Command Rate at 2T and suffering the consequent performance hit.
So we next tested the Patriot PDC1G5600ELK kit at its default 3-5-5-10 timings and 2.9V voltage and with 2T Command Rate. Unfortunately, our sample of the kit didn’t work at 700MHz. The maximum frequency the system was stable at was 664MHz.
So, not only the declared default memory frequency of 700MHz is just a marketing trick since it requires a significant worsening of the timings, but we can’t also confirm that the Patriot PDC1G5600ELK can work at this frequency – its specified frequency with the specified timings – at all!
Of course, we tried to increase the voltage above 2.9V, but this didn’t improve the overclockability of the memory kit (quite typically for Samsung TCCD chips, we should say).
The last word in this “Pseudo-DDR700 from Patriot Memory” story we want to say is about the heat dissipation of the chips. We noted in our practical tests that our Patriot PDC1G5600ELK kit would become very hot at work. For example, a temperature of 59°C was reported when the modules were tested for stability by the S&M 1.7.3 utility at 664MHz frequency.
So, we couldn’t get the promised 700MHz from our sample of Patriot PDC1G5600ELK memory. The manufacturer seems to have been carried away with proud marketing announcements, but didn’t support them with careful selection of memory chips. And still, the release of memory modules marked as DDR700 SDRAM, even though they proved to be not the best memory possible, put a thought into our heads.
The Patriot PDC1G5600ELK series is not just a pure hoax. Even though we were not lucky with our off-the-shelf sample, the PDP Systems engineers certainly had some PC5600-capable modules in their own tests. It means that some Samsung TCCD chips can overcome the 700MHz barrier. At least in theory. But in practice no one is going to set 3-5-5-10 timings and 2T Command Rate just for the pleasure to reach sky-high operational frequencies. We’ve never carried out such experiments in our labs. Maybe we should try?
Ok. Not so long ago we tested OCZ EL DDR PC-4800 Dual Channel Platinum memory modules and were left highly satisfied with them (for edtails see our articloe called DDR600 SDRAM Tested: OCZ EL DDR PC-4800 Dual Channel Platinum Review ). Particularly, this memory was stable as DDR640 SDRAM at 2.9V voltage, 3-4-4-10 timings and 1T Command Rate. It was logical to suppose that these modules would be stable at 700MHz frequency if the timings were slackened and the Command Rate set at 2T. Our expectations came true: the OCZ EL DDR PC-4800 Dual Channel Platinum memory was absolutely stable as PC5600 SDRAM at the standard settings of the Patriot PDC1G5600ELK.
It means that although PDP Systems was the first company to announce DDR700 SDRAM officially, memory modules capable of working at this frequency had already been available before. In fact, many high-quality memory modules on Samsung TCCD chips can work at 700MHz if you lift the timings up. Unfortunately, the Patriot PDC1G5600ELK modules do not belong here as concerns stable operation as DDR700 SDRAM.
But should we be sad at all about a memory kit not working at a high frequency with poor timings? Our performance tests will show now…
We will try to check how profitable it is to use DDR700 SDRAM in an Athlon 64 platform on a condition that you have to go for some serious concessions in terms of memory timings for the system to be stable in this mode. To perform this test session we took a system with an Athlon 64 FX-57 processor (2.8GHz default clock rate) and tested its performance at varying clock-gen and memory frequencies. At each memory frequency we chose the most aggressive timings that overclocker-friendly modules on Samsung TCCD and Winbond UTT chips permitted.
We took two pairs of modules from OCZ to perform our tests: OCZ EL DDR PC-4800 Dual Channel Platinum (on Samsung TCCD chips) and OCZ EL DDR PC-3500 Gold GX (on Winbond chips). The table below lists the tested modes:
CPU clock frequency
OCZ EL DDR
OCZ EL DDR
As you see, the processor frequency is nearly the same in all the modes, so any variation in the system performance will only be due to the differences in the memory subsystem configuration.
The testbed was configured in the following way:
Although the title product of this review, Patriot PDC1G5600ELK, doesn’t take part in these tests, the results will show us if DDR700 SDRAM is at all worth the trouble.
We first ran synthetic memory tests.
SiSoftware Sandra 2005 doesn’t think much about DDR700 SDRAM: the increase of the Command Rate parameter to 2T leads to higher memory latency as well as to lower bandwidth. So, the first diagrams of our tests already show that you shouldn’t expect much from DDR700 SDRAM.
ScienceMark 2.0 agrees with Sandra 2005 respecting the bandwidth reduction. As for the memory latency, there is a certain pattern here:
As you can see, the latency of DDR700 doesn’t suffer much from the Command Rate set at 2T. Thanks to the extremely high frequency, this memory subsystem has a normal latency, comparable to that of DDR400 SDRAM subsystems.
Since the effective system performance comes from both bandwidth and latency, we also ran PCMark05 to get an overall performance rating of each tested memory subsystem:
According to this test, the memory performance scales up along with the frequency, notwithstanding the worsening timings. This rule, however, doesn’t apply to DDR700 SDRAM. The performance of this memory type is close to the results of the 560MHz DDR SDRAM due to the Command Rate parameter being set at 2T.
Yet it’s not very correct to make a final opinion basing on the results of synthetic benchmarks only. Let’s go over to complex tests.
The popular SuperPi benchmark works the fastest on DDR622 SDRAM. The digits of the pi number are calculated faster at a higher memory frequency and the calculation speed doesn’t greatly depend on the memory latency. DDR700 SDRAM, however, performs worse than the leader and equals DDR466 and DDR510.
It’s different in 3DMark2001: DDR466 with aggressive timings wins this test, while DDR700 SDRAM is faster than DDR400 and DDR430 SDRAM.
Recent PC games are not very sensitive to the memory subsystem performance while the classic games Quake 3 and Unreal Tournament 2004 show their preferences more clearly. So, memory clocked at 450-500MHz and working at the minimal timings is the best choice for playing games. The alternative is to use memory capable of working at 600-650MHz with Command Rate = 1T. DDR700 requires setting the Command Rate to 2T and is not the best choice for games.
Although high memory frequency is most important in media encoding tasks, DDR700 SDRAM doesn’t perform brilliantly even here.
We conclude this test session with WinRAR, an application highly sensitive to the memory subsystem parameters. The DDR700 SDRAM is the worst memory type here, dispelling the last doubts among the jury about it.
Since this article is dedicated primarily to the release of Patriot Memory PDC1G5600ELK modules, we would like to say a few conclusive words about them first. The new product from PDP Systems seems very innovative at first glance, but this is only an outward appearance. The PDC1G5600ELK kit is built from ordinary memory modules based on Samsung TCCD chips and does not differ from other similar overclocker-friendly products. We tested the capabilities of these modules at overclocked frequencies and found that they couldn’t work even at 600MHz with the acceptable 3-4-4-10 timings of and Command Rate set at 1T. They perform somewhat better with the aggressive 2-2-2-10 timings, ensuring stable operation at frequencies up to 446MHz, but this is hardly a record-breaking achievement.
The manufacturer positions these modules as capable of working at 700MHz frequency. However, the modules are not stable at this frequency in practice, even despite such stability-ensuring (and performance-reducing) measures as poor timings and 2T Command Rate. That said, the Patriot Memory PDC1G5600ELK can be regarded as a rather average overclocker-targeted solution you should not expect any wonders from.
As for the DDR700 mode in general, this frequency is in fact nothing extraordinary for DDR1 SDRAM. As we discovered, this frequency is supported by the best DDR SDRAM modules for overclockers, based on Samsung TCCD chips. However, you must ease up the timings and set the Command Rate parameter at 2T to start your system up at 700MHz memory frequency. And as our tests have shown, it is perfectly senseless to use memory in this mode, since these stability-ensuring measures negate all the effect from the high operational frequency. 700MHz DDR SDRAM is just an empty marketing slogan as yet, rather than a real something. You should be aware of that.