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Fast Page mode became the most widely used access method for DRAMs, and is still used on many systems. The benefit of FPM memory is reduced power consumption, mainly because sense and restore current is not necessary during page mode access. Though FPM was a major innovation, there are still some drawbacks. The most significant is that the output buffers turn off when CAS\ goes high. The minimum cycle time is 5ns before the output buffers turn off, which essentially adds at least 5ns to the cycle time. Today, FPM memory is the least desirable of all available DRAM memory. You should only consider using this if it is either free, or your system does not support any of the later memory types (such as a 486 based system). Typical timings are 6-3-3-3 (initial latency of 3 clocks, with a 3-clock page access). Due to the limited demand, FPM is actually more expensive now than most of the faster memories now available. HyperPage Mode (EDO) The last major improvement to asynchronous DRAMs came with the Hyperpage mode, or Extended DataOut. This innovation was simply to no longer turn off the output buffers upon the rising edge of /CAS. In essence, this eliminates the column precharge time while latching the data out. This allows the minimum time for /CAS to be low to be reduced, and the rising edge can come earlier. In addition to a 40% or greater improvement in access times, EDO uses the same amount of silicon and the same package size. EDO has been shown to work well with memory bus speeds up to 83MHz with little or no performance penalty. If the chips are sufficiently fast (55ns or faster), EDO can be used even with a 100MHz memory bus. One of the best reasons to use EDO is that all of the current motherboard chipsets support it with no compatibility problems, unlike much of the synchronous memory now being used. Even with all the stated advantages, EDO is no longer considered mainstream. Most manufacturers no longer produce it, or have limited production. It is only a matter of time before the prices begin to rise, and the equivalent size SDRAM module will be less expensive. If you already own EDO memory, there is no real reason to jump to SDRAM unless you require bus speeds above 83MHz. With a typical EDO timing of 5-2-2-2 at 66MHz, there is almost no noticeable improvement with SDRAM over EDO, and at 83MHz it is still negligible. If you require 100MHz bus operation, EDO will lag far behind current SDRAM in performance even if it does operate at that speed due to the need for 6-3-3-3 timings. On the other hand, with EDO being phased out, you will likely find SDRAM to be equal to or even lower in price. Burst EDO (BEDO)