Intelligent Memory: 16 GB RAM modules for Broadwell notebooks
Those interested in ThinkPad notebooks like the X250 or T450s had to live with a big disadvantage: Lenovo only equips the two business notebooks with one RAM slot, which limits the maximum RAM capacity to 8 GB (X250) or 12 GB (T450s, 8 GB + 4 GB on-board), respectively. Devices from other manufactures, for example the AsusPro Advanced BU201LA suffer from the same problem.
The relatively small RAM manufacturer Intelligent Memory has found out how to make normal SODIMMs for notebooks (unbuffered, without ECC) with capacities up to 16 GB. IM uses a trick borrowed from NAND flash: By stacking two 4 Gbit chips in a 30 nm process, the manufacturer gets one 8 Gbit package and 16 units of these give us a 16 GB module. While this might sound quite simple, it is a huge technical challenge. Because of the high speeds in DRAMs, even latency differences of a few picoseconds could cause problems.
Unfortunately, such big modules are not compatible with every memory controller without further ado. According to IM, current and older AMD processors support the new 16 GB DIMMS without problems, but Broadwell processors are the first compatible Intel CPUs. The RAM modules were already successfully tested in a ThinkPad X250, which gives hope for other models. We will check the compatibility with different notebooks in separate tests soon.
First manufacturers are already listing the 16 GB module (IMM2G64D3LSOD8AG-B15E) with a unit price of just under 350 Euros. Thus, the price per GB is significantly higher than a typical kit consisting of two 8 GB DIMMS currently available from about 120 Euro depending on the manufacturer. Substantial customers from the business or workstation segment could still be a target group. For example, a ThinkPad W541 with 4 slots could be equipped with up to 64 GB. A small disadvantage: For the time being, the manufacturer only offers DDR3L-1333 (1.35 V), but a faster DDR3L-1600 version is expected to follow.
In the meanwhile, we received the RAM and it worked in various Intel Broadwell and AMD notebooks. Apart from the sightly low bandwidth because of the DDR3L-1333 standards, which can especially cause small performance losses when using the integrated graphics cards, we could not detect any abnormalities in use. A quick test with Prime95 Blend proves, the systems still run absolutely stable.
As announced by the manufacturer, the modules are not compatible with Haswell CPUs. Following is a list of the devices we have already tested.
- Lenovo ThinkPad W550s (Core i7-5500U, Broadwell), 2x 16 GB
- Lenovo ThinkPad E550 (Core i3-5005U, Broadwell), 2x 16 GB
- AMD Kabini prototype (A4-5000), 2x 16 GB
- HP ZBook 15 G2 (Core i7-4910MQ, Haswell), 2x 16 GB: black screen, system does not boot