The Module

The Overclockerz Store is marketing the OCZ Performance Enhanced SDRAM as 150MHz 2-2-2 SDRAM. According to them, they hand test each module to 150MHz and beyond at CAS 2-2-2. That's pretty amazing, considering their low price.

At first glance, the 128MB OCZ Performance Enhanced DIMM appears to be nothing more than an ordinary single-sided 168-pin SDRAM module. The only sign that this is from OCZ is the large OCZ Performance Enhanced label stuck across four of the SDRAM chips.

The single-sided layout allows for less noise, compared to a double-sided layout. This should help improve the overclockability of this DIMM, although I suspect that the availability of the 128Mbit SDRAM chips required also played a part.

On the back, there's nothing but a plain white 128MB label that confirms to any doubting Thomas that this truly is a 128MB module. :)

The Chip

Now, let's take a closer look at the SDRAM chips used in the 128MB OCZ Performance Enhanced SDRAM DIMM.

As you can see from the picture on the right, this DIMM is using chips from Infineon. BTW, OCZ also uses chips from Micron so don't be surprised if your OCZ Performance Enhanced SDRAM DIMM comes with Micron chips instead.
    

But do you notice something funny? Check out the chip label. A check reveals that the chips is actually Infineon's 7.5ns SDRAM which is designed to run at only 133MHz 3-3-3! So, how does this DIMM actually make it up to 150MHz 2-2-2?

Simple! All OCZ needs to do is buy Infineon's 7.5ns SDRAM and regrade them in the expectation that a significant portion can be overclocked to 150MHz. This is because Infineon don't have separate lines for each SDRAM speed grade. They just manufacture SDRAM and then grade them according to the market needs. So, there's a very good chance that the 7.5ns Infineon SDRAM can actually run a lot faster than the rated 133MHz.

So, OCZ retests Infineon's 133MHz 3-3-3 SDRAM for chips that can make it up to 150MHz 2-2-2. These are then set aside to be used in OCZ's Performance Enhanced DIMMs. Those that don't make the grade are then used in their Value line of PC133 3-3-3 SDRAM DIMMs. This allows them to create 150MHz 2-2-2 modules using the much cheaper PC133 3-3-3 SDRAM.

Here are some details on the Infineon HYB39S128800CT-7.5 SDRAM you might be interested in :-

• No. of banks : 4
• Speed @ CAS 2 : 100MHz
• Speed @ CAS 3 : 133MHz
• Recommended operating voltage : 3.0V-3.6V
• Synchronous to positive edge
• Power dissipation : 1W
• Fabrication process : 0.17 microns
• Package : P-TSOP-54

Now, let's see just how well this DIMM works!