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Difference and Comparison between DDR2 and DDR3 memory

Most of the recent notebooks and computers of both AMD and Intel are coming up equipped with DDR2  and DDR3 memories. This FAQ should help you understand the difference in the DDR2 and DDR3  memories.

Q. Can I insert a DDR3 memory module in a motherboard designed for DDR2 memory ?

A. No, you can not insert DDR3 memory module in a motherboard designed for the DDR2 memory. They have different sockets and the pin outs.

Q. What are different speed grades of the DDR2 versus DDR3 memory available.
A. The DDR2 memory is available officially available in the speed range of 400 to 800 Megabits  per second. The DDR3 memory is officially available in the speed range of 800  to 1600 Megabits per second. Speeds higher than 800 Mbps in DDR and higher than 1600 in DDR3 are also available,  but they are not officially supported.

Q. How much is the real improvement in the memory throughput in DDR3 over DDR2

A. This is very good question. The actual throughput measurement involves the motherboard, CPU among other things and it makes the comparison difficult. However, there has not been any significant improvement in the performance between DDR2 and DDR3 even with  the marked increase in the frequency. It is only after DDR3-1333 that you start to see something real in terms of the improvement in the throughput. Various benchmarks have reported 5% to 1% improvements depending upon the memory configuration and the speed grades of the memory you are comparing.

Q. I heard that the Cache Latency of DDR3 memory is higher than that of the DDR2. And that this makes DDR3 memory slower than the DDR2 memory.

A. You are correct in that the Cache Latency of the DDR3 memory is higher than the DDR2 memory. Cache Latency is defined at the time between the issue of the read command from the processor and the time when the data from the memory actually becomes available. It is measures in the units of clock cycles. A higher cache latency in DDR3 means that it becomes slower. However, cache latency is not the only thing determining the overall performance and speed of the DDR3 memory. The higher speed of the DDR3 memory more than makes up the issue of the cache latency.

Q. How about power consumptions ? Which of these two memories consume lower power ?

A. DDR3 memory was designed with power consumption in mind. DDR3 consumes substantially lower power than the DDR2 memory. This especially helps the notebooks that are supposed to work on batteries and the battery life is a concern.

Q. What technological challenge is presented in the architecture and design of the DDR3 memory.

A. Since DDR3 memory works much faster than the DDR2 memory, there are Signal Integrity  challenges to keep the memory part running at much higher frequency. Also the DDR3 memory has been designed to work at lower voltage level. Lower voltage means that a small amount of noise in the power supply rail can lead to error and failure. This is manifested in terms of system hanging. The designers using DDR3 must analyze the platform and the system motherboard to ensure that it stays robust under all conditions of temperature and voltage variations.

hardware

The Intel’s core i7-970 processor is one of the most powerful processor available at the time of writing ( July 2010). Intel indicates the budgetary price of $885.00 in quantities of 1000. This is pretty much in line with the processor being available at newegg at $899.

Clocked at 3.2 GHz, the intel core i7-970 has 6 cores with the ability of 2 threads each core, giving it ability to run 12 Hyperthreads simultaneously. The turbo boost technology allows increase in the processor frequency to 3.46 GHz depending upon the demand. A whopping 12 MB of the L3 cache adds performance boost to the processor.

The processor has integrated memory controller. The core i7-970 has three memory channels ( the i3 and i5 lines have just two memory channels). This significantly increases the memory transfer rate.

Available in 1366 pins socket FCLGA1366 – core i7-970 has a maximum power consumption of 130 W. If you are looking for extreme performance computing you may like to look for Core i7-970 Processor in the desktop you are buying.

hardware

A detailed review was covered in Intel Core i5-450M review with emphasis on i5-450M processor in general and i5 in particular.

Several variation of the i5 processor are available and the table below lists out the differences in these processors.

Table : Intel Core i5 processor comparison comparison

Model	Frequency	AES Function
i5-450M	2.4GHz	No
i5-520M	2.4GHz	Yes
i5-580M	2.67GHz	Yes
i5-540M	2.53GHz	Yes
i5-430M	2.26GHz	No

A note on the AES function – The AES stands for Advanced Encryption Standard – and some of the i5 processors have built in capability for the AES encryption functions that helps speed up the encryption processors.

All of these processors have 512 KB of the L2 Cache and 3MB of L3 Cache. They all have integrated memory controller. The pricing for the higher frequency models in general will be substantially higher than the lower frequency models.

hardware

A large number of today’s ( as of July 2010) notebook are coming equipped with the Intel i5-450M processor. For example the flagship notebook frm HP – the HP Envy 17 has intel i5-450M processor. If your notebook has this processor or if you are planning to buy a notebook that has this processor you may like to familiarize with the capabilities of this processor.

The i5-450M is clocked at 2.4GHz and there are two things that will make this processor faster than a similarly clocked Core 2 processor. The first is that the i5 processor has integrated memory controller. What it means is that the processor communicates with the memory directly and does not has to go through another chip in between the processor and the memory. This reduces the latency and the increases the performance.

The second potential change the improves that performance in the processor as compared to the core 2 duo is the hyperthreading. With two threads for each processor there are 4 threads running that helps improve the performance when several processes are running in parallel.

There are also several architectural changes inside the processor chip all designed to reduce the power consumption and boost the performance as compared to Core 2 Duo. In essence, you are going to see a processor that is significantly faster than the core 2 processor.

The maximum power consumption of this processor is 35 W. Given the kind of the performance intel has done a great job in keeping the processor cool.

Unlike the i3 processors, the i5 processors do contain the turbo boost technology. What it means is that the i5-450M processor will normally be running at 2.4GHz frequency, but, if the processes demand, it will boost the frequency to 2.66 GHz.

The intel has some more details of this processor if you are willing to look at the specifications of this processor.

The integration of the Integrated Graphics and HD Graphics makes this processor especially suited for the gaming and the HD display. Many gaming and multimedia notebooks launched recently have used this processor.

The processor is packaged in PGA988 socket and will not fit in the older core 2 processor motherboards.

hardware

Most of the today’s lower end ( and thereby lower cost) notebooks and laptops are coming equipped with the Intel Core i3 U330UM processor. Familiarize yourself with the capability and shortcomings of this processor if you plan to buy a notebook that has Intel Core i3 330UM processor.

The Intel Core i3-330UM works on Ultra Low voltage. To consider the advantage of a processor working on low voltage you should notice the power formula that goes like P = V*V/R, where V is the voltage and R is the resistance. The power consumed by the processor is dependent upon the “core voltage” it runs upon. So of the core voltage is reduced from say 1.2V to say 1.0V, the power consumption reduces from 1.44/R waats to 1.00/R watts – this is close to 40% reduction ( I have not done pure math – but this is ball park number).
There are couple of things you should notice about Intel Core i3 U330UM, that makes it a faster processor than the similar clocked Core 2 Duo Processor at 1.2GHz. The first of them is the integrated memory controller. By integrated memory controller we mean that the processor communicates with the memory directly unlike in the core 2 Duo processor which communicates to a chip called North Bridge, which in turn talks to the memory. In core 2 Duo this leads to increases the overhead in terms of the time it takes for the processor to communicate to the memory and thereby it slows down the memory communication.

Another significant change is the Hyperthreading. Intel silently reintroduced the Hyperthreading in the Core i3 processor. With two core in the i3 and with two Hyperthreads in each processor means that there could be 4 Hyperthreads running at a time. This boosts the performance if several processes are running at a time.

Notice that the low clock speed of 1.2 GHz will still be a bottleneck if you are expecting the notebooks powered by Intel Core i3 U330UM to perform like a gaming notebooks.

However, by keeping the frequency low, it is possible to make the processor run at lower voltage which in turn reduces the power consumption and boosts battery life of the notebooks powered by Intel Core i3 U330UM. The power consumption of the Intel Core i3 U330UM is 18 Watt TDP (max.). This helps manufactures design notebooks that have higher battery life.

Now few more things about Intel Core i3 330UM – The first is the the core i3 processors does not have Turbo Boost to overclock the CPU cores. The Turbo Boost allows the increase in the frequency of the CPU based upon the demand. This is a great feature to have that balances the battery life ( when you are not using processes that demand huge processing power) with the on demand processing power at the cost of the battery life. If you are considering the Turbo boost feature consider looking at the i5 or the i7 processor.

One of the significant features in the Core i3-330UM processor is the integrated graphics card (also called Intel HD Graphics). The graphics unit is also referred to as GPU ( Graphics Processing Unit).What it means is that you will be able to play the HD graphics from, say a Blu Ray player without a significant glitch in the display. Since intel is not a basically GPU master, its GPU unit still needs some improvement.

In overall, the Intel Core i3, 330UM is a decent processor for low battery power consumption, moderate processing power and suited perfectly for home computing and traveling professionals. If you need higher processing power look for a notebook equipped with core i5 or core i7 processor.

hardware core i3