Hello. I am Gilgamesh.
If you don't know me yet, I have been digging around inside computers for more than thirty years. I watched MFM hard drives die, I replaced bulging capacitors, and I fixed motherboards back when throwing everything away was not yet the fashion. For me a soldering iron is not a decoration, it is a work tool.
And I have some news. From now on I will be writing every week about different hardware topics. Not because I suddenly want to become an influencer, but because my boss basically ordered me to make sure that the experience I gathered over the years does not just sit and gather dust between the workshop walls. If I have already seen this many machines taken apart and put back together, then maybe it can be useful for someone else too.
Our first topic is nothing else than the world of DDR4 and DDR5 memory. Many people think there is only a bigger number on the box, so it must be better. The reality is a lot more interesting than that.
_IMGP6298_smial_wp.jpg){kind=link}
What is DDR memory anyway?
DDR is short for Double Data Rate. It means that the data transfer happens on both the rising and the falling edge of the clock signal, so data is sent twice during a single clock cycle.
Over the years the technology developed a lot, from the first DDR through DDR2, DDR3 and DDR4, all the way to today's DDR5. Every generation brought higher bandwidth, lower power consumption and better stability, but every change also came with its own compromises.
DDR4, the trusted veteran
DDR4 started to be used more widely around 2014, and for many years it basically ruled the market. Its base voltage is 1.2 Volt, and most modules arrived with speeds between 2133 MHz and 3200 MHz. With a bit of tuning you could push them above 4000 MHz as well.
One of the biggest advantages of DDR4 is how mature it is. The BIOS of the motherboards knows it well by now, a lot of compatibility bugs were fixed over the years, and today it counts as a very stable platform. It is not a coincidence that many professional workstations still run on DDR4.
DDR5, not just a higher clock
Many people believe that DDR5 is simply a faster DDR4. This is not true. DDR5 got a completely different build, and the important changes are not the ones printed on the label.
Two independent channels
One of the most important differences is that a single memory module is split into two independent 32 bit channels. This allows a more efficient data handling, especially when a lot of smaller data packets need to be moved around.
The PMIC on the module
The other big change is that part of the power regulation moved onto the memory itself. This is done by a PMIC (Power Management Integrated Circuit). At first this looks like a small thing, but it allows a much more precise voltage regulation.
Lower voltage
The base voltage of DDR5 is already only 1.1 Volt. This means lower consumption, which is especially important for laptops and big servers.
ECC, but not the way many people think
On the internet I often meet the misbelief that every DDR5 is ECC memory. This is not true.
DDR5 modules really do have something called On-Die ECC, but this only protects the internal work of the memory chip. It does not replace the real ECC memory used in servers, which is able to give error correction toward the system and the processor as well. These are two completely different technologies.
Compatibility
This is the part where a lot of beginners make a mistake.
A DDR4 memory cannot be put into a DDR5 slot, and DDR5 memory cannot be used in a DDR4 motherboard either. It is not only the notch that sits in a different place, the electrical operation and the control are completely different too. Even if at first sight it looks similar, they are simply not compatible.
Common problems when using DDR5
When DDR5 arrived, a lot of users ran into different problems. The most well known ones are:
- very long memory training at the first boot
- black screen after a BIOS update
- unstable XMP or EXPO profile
- random restarts
- memory errors with too high clock speeds
Memory training is a completely normal process. In this case the motherboard is looking for the timings that let the memory run in a stable way, and at the first boot this can take even several minutes. Many people think the computer froze, when in reality it is just working.
XMP and EXPO
In the old days we simply put in the memory and it worked. Today the situation is a little more complicated.
Intel platforms usually use XMP profiles, while on AMD systems the EXPO became more common. These are ready made memory settings that automatically set the clock, the timings and the needed voltage. If XMP or EXPO is not turned on, a lot of memory runs only at base speed, so much slower than what it is actually capable of.
Which one is worth choosing?
There is no single answer here. It depends on what you already have and on what you are building.
When DDR4 still makes sense
If someone wants to use an existing DDR4 configuration for a few more years, there is no reason to panic. DDR4 still gives excellent performance today.
When DDR5 is the better bet
If we are building a new machine, especially next to a modern Intel or AMD processor, then on the long run DDR5 is already the better investment:
- higher bandwidth
- better future proofing
- more advanced control
- lower consumption
On the other hand you pay a higher price and, for now, you deal with more sensitive settings.
If you are not sure which one fits your machine, we keep both DDR4 and DDR5 modules in the shop, and you can always bring the machine in and we take a look together.
And what about LPDDR memory?
In the world of laptops and mobile devices we meet LPDDR4X, LPDDR5 and LPDDR5X memory more and more often. LP is short for Low Power, and these were designed mainly for energy efficiency:
- lower consumption
- lower heat
- better battery life
But in most cases these memories are soldered directly onto the motherboard, which means they cannot be replaced or expanded later. This is often an unpleasant surprise for those who want to expand the memory in a notebook years later, so before buying it is always worth thinking about how much memory you will need on the long run.
A few words about memory prices
It is also worth mentioning a phenomenon that more and more people run into lately. The memory prices started to climb significantly again. Because of this many users postpone the move to DDR5, or on purpose choose a well proven DDR4 platform instead. Thanks to this the DDR4 is basically living a kind of renaissance, not because it suddenly became faster, but because in price to value it can still be an excellent choice for those who do not want to spend unreasonably much on a new configuration.
Of course the change of the memory prices is not driven only by the demand. The production of the manufacturers, the changes of the semiconductor market, the arrival of new technologies and the events of the world market all have a serious effect on how much a memory costs from one month to the next. This is a complex topic that you cannot deal with in a few sentences, so I will write about it in more detail in a later article. We will look at what stands behind the constant change of the prices, when it is worth buying memory, when it is better to wait, and I will also share a few tips with which you can save a lot of money.
Summary
The difference between DDR4 and DDR5 is a lot more than what the number on the box suggests.
DDR4 is a mature, extremely stable technology by now, which will serve most users well for a long time still. DDR5 on the other side represents the future. It is faster, it has a more advanced build and it works with a more efficient energy use, but at the same time it needs more attention when it comes to the right BIOS settings and compatibility.
In computing there is no perfect choice for everyone. For some people the stability matters, for others the maximum performance. The point is to always choose the solution that fits our own needs, not the one that the marketing tries to push on us right now.
In the next article we dig deeper into the topic. We look at the world of memory tuning, we talk about timings, about the fine tuning of the XMP and EXPO profiles, about Gear modes, about the Command Rate, and also about when it is worth to set a memory by hand and when it is better to leave it alone. There will be stability tests, common mistakes and the little tricks that I learned in the workshop over the years.
Until then do not forget: a computer is not magic. Everything has a reason. And if something finally gives up for good... C'estalvie.