Winbond BH-5/CH-5 recognition guide


Guide has been made due to recent interest in legacy hardware overclocking, including DDR1 platforms like socket 939, socket 754, socket A or 478 where DDR1 were commonly used. Most of the Winbond based sticks can work with 500-550MHz frequencies on very low timings – 2-2-2-5 or even 2-2-2-2 which makes them a most wanted sticks used in competetive benchmarking. Unfortunately most of the information about them in Internet is not available, including pictures and reviews. Also, most of the best RAM of that era ended in collectors hands and getting those RAM sets is almost impossible. However, a lot of Winbond based IC were used in OEM sticks like Twinmos, Kingston, Vdata etc. Some of them are able to overclock very well, which makes them perfect for overclocking. Best news is, that they still can be found in auction services. I wrote a short guide based on my experience where to look for good RAM.

1. Winbond IC

First thing you should know is how Winbond IC looks. It has two very unique features – first one is two round marks on the top of the IC. DDR1 were very often relabeled, looking the markings on the IC won’t tell you the truth. If you spot those two round marks on the top you can be sure, that it’s Winbond based IC.

Second feature are two metal parts which can be seen on the side of the IC. All other IC look different in this place. Because it’s side (top or bottom), it can be easily seen without taking off the heatsink. It saves a lot of time when looking for good sticks.

2. Type of Winbond IC

  • Winbond BH-5/BH-6 – are considered to be the best, scales with voltage very well (up to 4V), made in 175 nm manufaturing proces. They can be found also as Winbond UTT, which are still Winbond, but untested.
  • Winbond CH-5/CH-6 – similar IC made in lower manufacturing proces (130 nm), doesn’t like voltage so much, 3,6V is considered to be the max, although the can die easily at those volts too. Doesn’t clock as good as BH-5, however they are much more common, they still can be found in OEM sticks.

Theoretically BH-5 can’t boot on CL3, I haven’t confirmed it yet.

3. Where to look:

There are still some RAM lists active in the Internet, so a lot of info can be found there. It’s actually very tricky to properly recognize the sticks, especially Corsair and OCZ had so many models and revisions, they also often change the IC in one model during the life of the product. OEM sticks are easier to properly recognized for me, because they don’t have heatsinks, so we can look for characteristic features which I mentioned. Below are samples of modules based on Winbond IC which I can personally confirm.

  • Twinmos @ BH-5 with 1A4T end of model numer
  • Twinmos @ CH-5 with AA4T end of model numer
  • Vdata on BrainPower PCB (not every module)
  • Kingston OEM PC2700 or PC3200, in this case not remarked
  • OCZ Gold PC3500 EL
  • Kingston HyperX KHX 3500 (old)

To be continued... thanks to my friend phobosq for sharing some useful information