Upgrading server hardware can be a gratifying, but also stressful experience. Since so many options are available on the market offering performance upgrades, storage expansion, and increased reliability, a buyer must do extensive research in finding the best solution for their application. With server memory playing a critical component to ensure efficient processing times, file accessibility, and high volume user activity for enterprise-level networks, it is imperative to be aware of existing and upcoming choices offered today. This article focuses on comparing two memory selections, DDR4 available in today’s market and DDR5 being developed for future availability, and may help to determine if upgrading to DDR5 (or to DDR4 for those out there still using DDR3 products) is best suited for your needs.
DDR4
Currently, the most recent available DRAM memory option is DDR4 SDRAM (double data rate 4th generation synchronous dynamic random access memory) and was released to the market in 2014. Being the successor to DDR2 and DDR3, its most noted improvements provide higher module density allowing for greater operating capacities in smaller physical space along with lower voltage requirements.Voltage & Power ConsumptionThe voltage difference between the DDR3 and DDR4 is small with the former using 1.5 volts and the latter needing only 1.2 volts. It can be lowered to 1.05 volts with some restrictions, which still isn’t very much to an average home PC user. However, from the perspective of network and datacenter administrators that oversee sizable server populations, this small decrease adds up considering thousands of DDR4 modules can be in service saving an ample cost applied to power all these devices. This calculates into an average 1 to 2W per module and average 15W saving per server, which is a 20% power reduction from the older technology. Operating at low voltage also increases reliability equating into better system stability over time. SpeedPerformance speed also saw an increase compared to DDR3, which was initially labeled with transfer rates at 800 MT/s (millions of transfers per second) and capping at 2133 MT/s. DDR4 transfer rates start at 2133 MT/s with premier flash storage server options such as Premio’s FlacheStream product line having options of operating at 2400MT/s. Future projections of DDR4 upgrades are predicted to even reach speeds of 3200 MT/s. This substantial increase has a direct relationship raising bandwidth, as well, providing a higher operating speed. Dedicated server applications saw the most improvement because of this feature due to their greater RAM bandwidth requirement.Pin PackageThese specification updates also brought about a physical pin change with DDR4. The pin package for DDR3 RAM uses a 240-pin configuration while DDR4 introduced a new 288-pin package. Because of the added pins, the modules height has been raised to 31.25mm compared to DDR3 standing at 30.35mm. The new pin arrangement provides hardware incompatibilities with DDR3 components, which poses as a large hurdle for IT professionals researching cost and labor effective upgrade options for their present application while making minor component changes. Though developing hardware technology expands to accommodate DDR4 and DDR3 configurations as a bridge to expand DDR4 coverage, this leaves limited options to those only looking to upgrade memory within their current computer architecture.LatencyFor those unaware of latency and its relationship to RAM, it’s understandable not to be aware of this spec when compared to other characteristics such as speed and capacity. Latency specifications refer to the amount of time taken for a processor to send a command and then for memory to make an appropriate response. This figure is measured in clock cycles when discussing it in regard to SDRAM modules and can be referred to as Column Access Strobe (CAS) latency or CL. Without getting too deep into this spec as opinions of its overall importance vary, DDR4 did not make a drastic improvement in this category, with some test results showing DDR3 and DDR4 having roughly similar results around 12-14ns. For more information about DDR latency tests, Crucial posted their results (Source: Crucial) and is an interesting read to those that want more details. Memory CapacityDDR4 standard memory capacity is available in various options ranging from 16GB to 64GB, its minimum amount doubling its forerunner where DDR3 capacity peaked at 8GB. Custom DIMM (dual in-line memory module) kit configurations are available providing varying operating speeds to meet the needs of high-end gaming platforms and beyond towards users utilizing top-tier video streaming and editing programs. Some recent kit modules available to date are offering DDR4 modules with 8 x 16GB capacity totaling 128GB of RAM. Most end-user consumers may not revel at RAM memory capacity, but at levels this high they will welcome the performance it provides. With the multitude of possible solutions and improvements to current traits in smartphones and tablets, the masses will be sure to appreciate new and innovative features unable to be realized until now.
DDR5
JEDEC (global leader in developing open standards for microelectronics) released plans to introduce a new DDR5 SDRAM specification in 2016. While the standard is still in development in JEDEC’s JC-42 Committee for Solid State Memories (Source: JEDEC), it is indicated that DDR5 will provide enhanced performance with better power efficiency when compared to prior DDR generations. Per plan, DDR5 will provide twice the bandwidth as well as density for larger capacity in comparison to DDR4. An article from Digital Trends reported that DDR5 memory specifications are expected to be finalized by JEDEC in 2018 (Source: Digital Trends), so developers will have to wait a little longer to find out what specification standards to expect from DDR5. Some experts were assuming the end of DDR DRAM with the release of DDR4 having the expectation of the next new concept of memory to be developed. However since server and PC have not encountered many drastic changes of late, the development of DDR5 may not be as surprising as once thought. With expected end-user availability in 2020 (Source: PCWorld), it will still be some time before the public gets their hands on this technology to reap the benefits of the increased speed and memory.So where does this leave those that are looking for memory solution upgrades? Unfortunately, no DDR version has ever been backward compatible with its predecessor. SDRAM cannot be mixed with DDR, DDR is not able to be mixed with DDR2, DDR2 cannot be used in DDR3 systems, and DDR4 is not compatible with DDR3. It may be too early to say, but if history repeats itself as if so often does, DDR5 will more than likely be incompatible with DDR4. Having these hardware limitations definitely hinders the number of available options users have today as companies are still adapting DDR4 memory solutions into current computing products. It took time for DDR3 to become a mainstay and it was only last year that Samsung help to speed up industry change toward DDR4 products by mass producing the first 10nm 8GB DDR4 RAM chips and their designated modules. As popularity for this increases, prices of these components will fall allowing DDR4 to become the standard and new innovative advancements will conceptualize and become reality right as DDR5 is released. Assuming the hardware changes that will need to accommodate for it, plan accordingly based on the current needs and performance, or lack thereof, from existing applications. Because computing technology is a fluid industry with few limitations and a high ceiling, but short-lived breakthrough triumphs, it may be best to take a wait and see approach when it comes to DDR5.
