Efficient and capacious memory modules

Evgenie Rudometov,

Victor Rudometov

authors@rudometov.com

Company Apacer Technology Inc. For sector of high-powered desktop computers offers the units of dynamic storage DDR2 calculated for frequency of 667 MHz

Dynamic storage concerns the major subsystems of modern computers. Now in desktop computers dynamic storage DDR2 SDRAM units dominate. Units of the given standard are released by a considerable quantity of the companies, whose brands are widely presented in the domestic market.

As one of known manufacturers it is possible to result company Apacer Technology Inc. (Further it is simple Apacer). The given company has been grounded in 1997 Acer Group and is one of its independent business units: structure Acer Group includes also such known brands as AOPEN, Winstron, BenQ, etc. Dynamically developing, company Apacer is one of the largest manufacturers of units of replaceable memory, permanently showing tendency to reaching of excellence of production.

For high-powered desktop computer systems company Apacer offers PC2-5300 units which size is in a band of 256 Mb – 2 Gbytes. They are released, as well as it is offered existing standards, in konstruktive DIMM, have 240 contact electrodes, a supply voltage 1,8 V.Vysokoskorostnye Apacer units are calculated for operation with a transmission frequency of data to 667 MHz.

One of variants of such units has been given by company Apacer for acquaintance and testing. Appearance of the given units is presented in a Fig. 1.

Fig. 1. Apacer PC2-5300 units and their marking

According to the marking resulted on a label (Fig. 1), each of the given units of dynamic storage possess size of 1 Gbytes. Other parametres are ciphered in UNB PC2-5300 CL5 characters. These letter abbreviations mean, that units are nebuferizovannymi (unbuffered), DDR2 SDRAM and calculated for operation with a transmission frequency of data to 667 MHz.

Here it is necessary to mark, that the important features are not only metrics of size and maximum frequency, but time responses (tajmingi, timing) which are closely linked to operation of units. They in aggregate with size and frequency substantially define productivity of a subsystem of dynamic storage, and through it and productivity of all system of the computer. The major metric is parametre CAS # (CL).

In considered units to the upper value of frequency there corresponds signal CAS # (CL) = 5. The last characters of the specified string testify To it the markings designated as CL5.

It is necessary to mark, that operation of units on high frequencies as a part of high-powered computers is accompanied by a considerable heat release. This circumstance leads to rise in temperature of chips of memory, that in the conditions of compact system tanks can negatively be mirrored in stability. For rise of stability of operation of the specified units designers have supplied with their double-side metal slices. On a plan of creators they should fulfil functions of cooling heat sinks for memory chips with which they have the thermal contact electrode.

To estimate productivity and to check up working capacity of Apacer PC2-5300 units in different frequency modes it is possible in the course of testing.

Pattern of the system used in testing:

·         Motherboard AsusP5AD2-Premium (a chip set i925X, memory DDR2, the slot of video PCI Express x16, ports PATA and SATA, BIOS Vendor — American Megatrends Inc., BIOS Version — 1009.002),

·         Processor IntelPentium  4 with clock rate of a kernel of 3,4 GHz (LGA 775, kernel Prescott, the bus of 800 MHz, processing technique Hyper-Threading),

·         Dynamic storage DDR2, two units on 1 Gbyte Apacer PC2-5300, two channels,

·         ATIRadeon X600XT Videoadapter on bus PCI Express x16,

·         Disk drives on hard disks SeagateST3400832AS (Barracuda 7200.8, 400 Gbytes, 8 Mb of the cache memory, 7200 rpm, Serial ATA/150),

·         the Operating system of Windows 2003 Server Enterprise Edition, Service Pack 1.

As the testing tool package SiSoftware Sandra 2004.7.9.129 used.

In the course of the analysis of components of test system one of the package programs, having the name «Mainboard Information» («the Information on the motherboard»), among a considerable quantity of data has output the information on memory modules in the following form:

«Apacer Technology 1024MB 16x (64Mx8) DIMM DDR2-SDRAM PC2-5300U-555-4512 (CL5 up to 333) (CL4 up to 267) (CL3 up to 200)».

The given sequence represents decryption of a code of chip SPD. The given chip allocated on each memory module, contains the information on automatically installed functional modes of a subsystem of memory. The specified sequence, except the name of the manufacturer — companies Apacer and structures of chips applied as a part of units, contains memory type — DDR2 SDRAM and instructions on frequency potential — PC2-5300. The last number means, that the manufacturer guarantees DDR2 unit operation on frequency of 667 MHz, on which the data flow (Bandwidth, a band) to 5300 Mb per second is reached . The quiescent operation of the given units is supported by installation of appropriate values of parametres. Thus for smaller from standard frequencies, a component of 200 MHz and providing a transmission frequency of the given 400 MHz (DDR2-400), parametre CL=3. For the following standard frequency — 267 MHz (DDR2-533) is recommended to be made this parametre a little smaller — CL=4. For the upper recommended frequency reaching 333 MHz (DDR2-667), — CL=5. It is necessary to mark, that the last value coincides with the value specified on marking, superimposed on the labels pasted on units (a Fig. 1).

To high-speed parametres of a subsystem of dynamic storage testifies screenshots of windows with results of testing. The output data are received by means of the appropriate program units which are a part of package SiSoftware Sandra 2004.7.9.129.

The first of these tests — «Cash and Memory Benchmark» («the cache memory and memory Test»). The output window shows productivity of a subsystem of memory and a cache memory (processor-cache memory-chip set-memory) in comparison with other systems. The screenshot of the given window is presented in a Fig. 2.

Fig. 2. Results of the test «Cash and MemoryBenchmark»

The following test — «Memory Bendwidth Benchmark» («the Test of capacity of memory»). The output window shows productivity of a subsystem memories (processor-chip set-memory) in comparison with other systems. It skroinshot it is resulted in a Fig. 3.

Fig. 3. Results of the test «Memory Bandwidth Benchmark»

Estimating the resulted results of testing, it is necessary to mark, that in the selected pattern of hardware automatically installed functional mode of a subsystem of memory does not allow to realise frequency potential of Apacer PC2-5300 units to the full.

It is linked by that the motherboard created on a chip set i925X, supports processors with transmission frequencies of data on the bus not above 800 MHz. By operation with high models of processors for the memory bus the clock rate of 267 MHz providing 533 MHz for data transfer is automatically installed  . Such mode corresponds to a band of 4300 Mb per second.

However motherboard AsusP5AD2-Premium allows to instal in a manual mode of customisation BIOS Setup for a subsystem of memory modes 400, 533, 600 MHz. This possibility also has been realised in the course of led testing (a Fig. 4). It is necessary to remind, that at a choice of frequency of 400 MHz Apacer PC2-5300 units are perceived as PC2-3200, and at frequency of 533 MHz — PC2-4300. At installation of 600 MHz the given units have been identified as components of dynamic storage of standard PC2-5300.

All specified variants are presented in a Fig. 4.

Fig. 3. Activation of the computer system with installation for a subsystem of dynamic storage of modes 400, 533, 600 MHz

For each of three specified frequency modes officially supported by the motherboard of the used hardware-software complex, testing by means of the program component «Memory Bendwidth Benchmark» has been held. Results of the given research are presented in Table 1.

Table 1. Results of the test «Memory Bendwidth Benchmark» for different modes of the bus of memory

Benchmark	Modes of the bus of memory, MHz
	400	533	600
RAM Bandwidth Int Buff’d SSE2, MB/s	4750	5014	5063
RAM Bandwidth Float Buff’d iSSE2, MB/s	4747	5013	5061

In all three selected frequency modes, predictably, Apacer PC2-5300 units have shown a stable operation with productivity high level, that however, and it was expected from products of the given manufacturer.

In summary it is necessary to mark, that the potential put in pawn in Apacer PC2-5300 units to the full can be realised only at usage of processors with a transmission frequency of data on the system bus of 1066 MHz, of course, under condition of their appropriate support by the architecture of motherboards, BIOS and the software.

Memory modules ApacerPC2-5300 have been given by the European representation of company ApacerTechnologyInc.