Released sometime before June 25, 2005, the i-RAM
is a solid-state drive
produced by Gigabyte
which has four DIMM
slots to allow PC DDR RAM
to be used to store data.
It connects via a SATA port and is seen by the PC as a hard drive, and may therefore be booted from directly. However, the i-RAM is bottlenecked by the SATA interface, limiting bandwidth to a maximum sustained throughput of 150MB/sec. This speed limitation is offset by near instant access, with latency results of 0.1ms recorded.
DRAM however is volatile, so any loss of power will cause loss of data. The i-RAM is powered by plugging into a PCI slot, which powers it while the PC is plugged in (using standby power if the PC is off). It also has a 16 hour battery, which operates when the PC is unplugged or there is a power outage.
The i-RAM supports Unbuffered / Non-ECC DDR 200/266/333/400MHz RAM modules of different capacities (up to 1 GiB), speeds and brand for a maximum capacity of 4 GiB. Because of this, the i-RAM is very expensive per GB, but offers a silent storage method with higher responsiveness and performance than a traditional hard drive.
- Fast transfer rate
- Fast access time
- No moving parts
- Lower cost than traditional solid-state drives
- Unlimited write cycles compared to flash memory
- High cost compared to traditional hard drives
- Low capacity (4 GB maximum)
- High power consumption compared to hard disk
- Transfer rate restricted by SATA 150 bus (1.5Gb/s)
- Takes up one PCI slot
- Not physically compatible with all double-sided DDR RAM modules due to tight spacing
- All data is lost if there is a loss of power for more than 16 hours
- The battery can fail, potentially difficult to find a replacement battery
- Adding memory wipes the data from all sticks
- Increases standby power
Launched without so much as a press release, the i-RAM BOX became available to purchase in late July or early August 2007. It is essentially a full-width, half height drive bay implementation of the PCI revision 1.3.
Its main differences are:
- Half height 5.25" drive bay format
- No longer requires a PCI slot
- Uses a standard 24 pin ATX (motherboard) power cable for standby current (Y cable supplied)
- Uses a standard 4 pin Molex connector for power in use
- A fan header appears on PCB
- Slightly more spacious PCB layout
Otherwise it appears to be identical to the PCI version. It is unknown quite why this version based on the old PCI design was released rather than the second generation model shown in 2006; design changes would have been minimal due to the programmable Xilinx Spartan chipset. Most pundits expected changes to support 2GB RAM modules (possibly DDR2) and most importantly SATA 3Gb/s.
Second Generation i-RAM
The second generation i-RAM, GC-RAMDISK, was on display at Computex
2006 . Rather than using a PCI slot for powering the drive, Gigabyte had implemented the GC-RAMDISK as a 5.25" drive unit powered from a four-pin molex connector.
The drive supports four DDR2 memory modules of up to 2 GiB for a total capacity of up to 8 GiB and the interface supports SATA 3.0 Gbit/s, which doubles the transfer rate compared to i-RAM.
Although this version of the I-RAM was displayed at Computex Taipei 2006, during final revisioning it lost DDR2 and the higher capacity support. The released GC-RAMDISK still only supports up to DDR-400 with a total storage capacity of 4GiB.