The Gigabyte iRAM PCI Card
At first glance, the Gigabyte iRAM doesn’t look like anything particular different from what we have seen before: a PCI card with some connections for other devices. Memory risers have existed in the server for quite some time.
On the card’s face there are four DIMM slots that support DDR memory modules, a single red SATA controller that supports the original SATA 150 specification, a black box that contains the battery backup for the iRAM and some custom logic to make all these items work together.
There is nothing hiding on the back of the card either, with the exception of a couple of chips, one being a single MOSFET for power regulation to the PCB.
The iRAM features only a single SATA connection that allows it to communicate with the motherboard that it is plugged into. Using a standard SATA-I 150 MB/s connection, the custom emulation logic presents the iRAM as a standard hard drive to the motherboard and can be utilized without any drivers. In fact, though Gigabyte does have an approved list of chipsets that will work with the iRAM, any SATA controller should be able to communicate with it without any software or BIOS configurations required. This is one of the key benefits of this solution that Gigabyte brings to the table.
While the iRAM is plugged into the PCI bus and the system has power (even standby power while the unit is off but attached to a power supply), the battery is being charged by the power flowing over the PCI bus. This somewhat solves the problem of the volatility of memory modules. After all, using the iRAM as a partition to save something to would be more than pointless if all the data were erased every time the system was turned off.
When the unit does not have power, or while the card is out of the system (while you move the card to some other system, for example) Gigabyte attached a small battery to the board that has the responsibility of keeping your data from disappearing into oblivion. This battery sends enough of a current through the DIMMs to keep them refreshed and thus keeps the data in working order.
In my testing, the battery lasted around 4-5 hours when unplugged from the system after it had been fully charged on a working system for a day or so. Gigabyte did supply some small LED lights on the PCB that indicate if the unit has power but unfortunately they don’t really indicate the battery level so you never know how much time you might have until your data is going the way of the dodo. This can be a big issue obviously, so the best idea is to just make sure you never take the iRAM out of your system and forget about it.
In the box with the card you get a very simple manual, a CD with the manual in PDF format as well as an angled SATA cable that will keep the iRAM from interfering with any other PCI cards your might have in the system.
Here we see a fully populated iRAM sporting 4 GB of total memory. The iRAM only supports a maximum of 4 GB of memory total with four 1 GB modules. It don’t support ECC memory officially and it was hit or miss in our testing with all the memory in our office here on it. However, standard DDR modules had no problems being mixed and matched together with other modules speeds, sizes and brands.
Gigabyte tells us that the modules are actually only running at around 33 MHz on the card and that speed is more than enough to saturate the 150 MB/s SATA bus on the card. Timings are set fairly lax as well, so it makes sense that any modern DDR memory should be able to handle the speeds. Gigabyte does have a list of recommended modules but we didn’t feel like we had to follow it.
Just to play around, we could get four modules installed with heat spreaders on the iRAM, though Gigabyte tells you not to. And since the modules were physically straining the retention modules we strongly recommend you remove any heat spreaders before installing the memory. Also, it is running so slowly in relation to typical memory speeds, heat won’t be an issue.
