- Improvements for XMP profiles of the OCZ DDR3 PC3-12800 Intel Extreme Edition 4GB RAM kit
This tutorial will explain how to use XMP Enhancer Professional to modify Intel XMP profiles as an overclocking extension to the SPD firmware of DDR3 SDRAM memory modules.
For this purpose we have chosen our notorious OCZ DDR3 PC3-12800 Intel Extreme Edition 4GB RAM kit. The Ordering Part Number of the 2GB module is OCZ3X16002G. As you remember, this is the second time we deal with modules of that series. Although OCZ Technology claims that the RAM kit is an excellent choice for outstanding overclocking, users are running into a problem where they cannot get to run the modules at 800MHz from XMP Profile 1 of SPD. The problem is also related to the 2GB RAM kit (2x1024MB) since it has the same off-tested XMP profiles. So, let's see what is wrong with the XMP Profile 1.
The first step is to load SPD data into Hex Editor of Thaiphoon Burner. Now press F7 or clock on Tools and select XMP Enhancer.
According to the screenshot above, the XMP Profile 1 enables to run the memory module at the highest JEDEC compliant frequency of 800MHz. But there are some common mistakes made by OCZ engineer who have created the XMP Profile 1. In most cases these mistakes will not allow 800MHz to be achieved, except a black dead screen appearance at POST control.
So, what is wrong?
Minimum CAS Latency Time (tAAmin)
A value of 70 MTB units or 8.750 ns is out of range for DDR3-1600 data rates. The minimum time for tAAmin is 80 MTB units or 10 ns which means all timing parameters of the memory module will comply with the DDR3-1600G specification. This is the main mistake and it has to be corrected first.
Minimum CAS Write Latency Time (tCWLmin)
This latency time should be programmed in the same fashion as tRPmin. A value of 80 MTB units is typical.
Minimum RAS# to CAS# Delay Time (tRCDmin)
A value of 70 MTB units is too low and does not comply with any DDR3 speed grade specification. To meet the DDR3-1600G data rate the parameter should be set to 80 MTB units.
Minimum Row Precharge Delay Time (tRPmin)
The fundamental formula of tRC=tRAS+tRP is always ignored by SPD firmware engineers from OCZ. They seem to be not aware of it. According to properly selected delay times for tRAS and tRC signals, tRP can be calculated from the formula above and should be set to 80 MTB units.
Minimum Refresh Recovery Delay Time (tRFCmin)
720 MTB units are suitable for 512Mb SDRAM chips. In accordance with JEDEC’s DDR3 standard tRFC should be programmed to 880 MTB units since all memory modules of the OCZ DDR3 PC3-12800 Intel Extreme Edition employ 1Gb chips.
System CMD Rate Mode
Since the parameter has not been specified, we can program 16 MTB units meaning 2T is to be set.
Module Voltage Level
Due to increased delays the voltage level can be lowered to 1.80V form 1.90V.
Finally, your XMP Profile 1 should look like on the pictures below.