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Comment by igravious | Hacker News Reader

64GB! Sixty-four! For a desktop/laptop architecture! At 64GB (GiB?) main memory we're getting to the point where you could copy the entire working set of the OS to memory from disk on boot and then simply save to disk periodically. So long as you have a battery/UPS that'd work. Is that a crazy?

I'm currently on 3rd gen, the i7-3537U. My dream machine would be 13/14" laptop w/ 1080p (though 4k-ish wouldn't hurt), Skylake i7, usb-c, hdmi out, 16GB RAM, 256 decent SSD. Have I forgotten anything?

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I would say it's very sad that we have only 64GB. We should be allowed to install at least 128GB or 256GB in consumer grade mainboards. Similarly for a developer workstation one has to choose a Xeon to get more cores, but a smaller GPU and twice as many cpu cores in the non-Xeon line would be great because enthusiasts don't use the iGPU anyway. Developers don't need a fast GPU unless they really need one and then any iGPU is too little too slow so most chips should have more cores in place of bigger iGPUs. It's true that your office clerk workflow doesn't benefit from more cores due to legacy software, but software developer workflows benefit a lot when building code or running virtual machines or running (modern) concurrent applications. It's very very sad indeed that AMD is the only x86 vendor who puts more cores on consumer chips. Let's hope Zen will force a change.

Well, they're described as being "enthusiast" chips but the core i7 line does have 6 and 8 core versions: the 5820/5930 and the 5960 respectively.

We are not consumers. Intel would be foolish to optimize their consumer chips for us. If you want a workstation class machine you buy a Xeon. Adding memory channels is not free, and with 4 channels you get 64GB given current DDR4 capacity.

Don't people use GPUs all the time now because of Netflix and movie streaming? My old laptop's GPU would always kick in when I played something in 1080p.

I believe that streaming video can make use of GPU acceleration for decoding (to take some load off of your CPU).

> 64GB! Sixty-four! For a desktop/laptop architecture!

and still no ECC support, sigh

Cannot upvote enough. At this density, and considering caches will have persistence of days (if not more) in the main memory, random errors become a major issue. ECC should have became a standard in system memory 5 years ago already.

Wait is that true? There is no error correction in system memory? That sounds like a huge waste. Usually with coding not only reliability increases but you can decrease power consumption a lot too (so you're not "fighting the noise" with power only).

Yes, exactly true. Some libraries (like innodb) actually checksum all contents in memory to self-detect when corruption is happening. Most applications and libraries trust system memory too much and can read corrupted data at any given time.

Another fun way to get corrupted memory is to have some data swapped to disk, but have disk corruption, then have the corrupt disk data restored to memory. Bam. Instant invalid data in memory, but not caused by memory.

Many hashes are fast these days and should be used as checksums in more places since ECC isn't as common as it should be (and ECC doesn't detect all errors anyway).

> and still no ECC support, sigh

Are there any technical reasons not to have ECC by default, or is it just market segmentation?

Market segmentation. Core i{5,7} with ECC support is sold as Xeon E3.

For a while some of the Xeon E3s were the thing to buy, as they were sold at lower prices than the equivalent i7 CPUs (Xeons with 4 cores+HT and lots of cache were sold at the same price as the quad or dual+HT i5s), but this was "fixed" and now the cheap Xeons are crippled (no HT anymore).

What about motherboard support? I can't usually find any motherboard with ECC support that also has decent onboard sound...

Don't know about the quality of the support†, or what "decent" onboard sound is, but Supermicro sells a bunch of boards that support 1 or 2 Xeons (and generally also support consumer chips), ECC and have onboard sound. E.g. for the low, low price of $289 this board http://www.newegg.com/Product/Product.aspx?Item=N82E16813182... will support two processors, up to a half terabyte of memory, and has a Realtek ALC888 for 7.1 channels of sound.

†I'm using a one processor chip X9SAE to type this with, with HDMI output with sound included to my receiver and then monitor.

ECC support + decent onboard sound seems like a niche feature combination (at least in the Intel world where ECC support means buying a Xeon and a compatible server/workstation motherboard). Some AMD consumer boards do support ECC if you want to go down that route (e.g. http://www.asus.com/us/Motherboards/M5A97_PLUS/specification... ).

Not sure of your particular usage case but wouldn't it be just as easy to pick up a cheap (or decent) sound card that would meet or beat anything onboard could do? I personally tend to stick with onboard because it does what I need (sound for music and movies) and I use external sound interfaces when I want to mess with anything requiring more sound performance/options (like recording or making my pitiful attempts at producing music).

ECC memory has a small performance overhead, and is slightly more expensive (e.g. 12%).

It is segmentation for sure -- the chipsets and processors can easily support it -- and many of the people throughout this thread really should only be looking at Xeons. If 64GB of RAM and non-ECC memory is really such a problem, which it is for a vanishingly small percentage of users, go with a workstation chip at a small premium and have it all.

It's notable that effectively no mobile devices use ECC memory. Tablets don't. The vast majority of desktops don't. If you believed the rhetoric, these should all be crashing and destroying lives regularly. It turns out that ECC comes into play very, very infrequently. I would never buy a server that didn't have ECC, but on my desktop it just really doesn't matter that much.

What's the performance overhead of ECC come from? I know registered memory has a small but measurable latency penalty, and ECC modules are often also registered, but a simple parity check in the memory controller should be a pretty fast circuit.

These days ECC testing is supposed to be integrated into the CPUs.

Enthusiast testing seems to support this with overhead being <0.5% even for Reg ECC:

https://www.pugetsystems.com/labs/articles/ECC-and-REG-ECC-M...

we're getting to the point where you could copy the entire working set of the OS to memory

I've run diskless, boot-from-network systems with 2 to 4 GB RAM with the entire OS+data+servers in memory. If you know your exact sizes, you don't need giant RAM.

As far as desktop or interactive systems go, in 2009 I made a desktop with 24 GB RAM which essentially never read from the disk after everything got cached appropriately.

save to disk periodically.

That's what your kernel does. There's a long history of flushing dirty pages back to disk.

My dream machine would be

It looks like you want a MacBook Pro from 3 years ago?

I have to admit, at the moment, the one thing that fills my laptop memory the most frequently are browser tabs. There has got to be a better way -- and I know there are solutions, but their UX have failed me so far. Hardware advances are nice, but software/UX still has a long way to go.

>There has got to be a better way

Sure: don't open so many tabs.

> 64GB! Sixty-four! For a desktop/laptop architecture! At 64GB (GiB?) main memory we're getting to the point where you could copy the entire working set of the OS to memory from disk on boot and then simply save to disk periodically. So long as you have a battery/UPS that'd work. Is that a crazy?

That would be very unreliable, would cause huge loading times, huge powerdown times. Also modern OS uses free memory as a disk cache, so you are already getting all speed benefits.

So basically you might just do find / -type f -exec cat {} > /dev/null \; to fill your disk cache if you have enough memory.

My 4 years old mid range CPU and motherboard supports 32GB.

Linux does copy-to-ram for at least decade (Slax, Knoppix...).

> My dream machine would be 13/14" laptop

Toshiba Portege Z30 supports 16GB RAM, in theory it handles 32GB RAM. I am waiting for new version with Skylike and retina.

Amen, for linux's copy-to-ram!

I use the Slitaz distribution on my old Compaq computer from 1999, and wow! Even with only 384 MB of RAM, the system is blazing fast, all thanks to copy-to-ram!

A 64GB maximum is seriously disappointing - I upgraded my 3 year old pc to its 32GB maximum a few months ago and right now it's using all that plus 27GB of swap. I could easily and usefully use much more.

Until we have persistent memory. 3D X-point is a pragmatic step in the direction. It would be weird to reorganize a system around lots of RAM and persistent dram/flash hybrid.

The next MacBook Pros should have Skylake processors in them. Might feature USB-C, too. Although the i7 might be exclusive to the 15-inch model.

Dell's XPS[1] range should eventually get a refresh also, but Dell seems to have a habit of launching laptops juuust before Intel does a refresh which is myopic or careless or I don't know what.

Looking at those benchmarks[2] the Skylake i5 is no slouch but I just have an aversion to the i5 for no rational reason whatsoever. Seems to be clocked lower and doesn't have hyper-threading. If you're going to get the top of the line CPU and chipset you may as well go for the i7 rather than the i5. is my thinking. I guess the i5 exists to create mid-range gear -- pair an i7 with a dedicated GPU, i5 uses integrated; i7 gets a retina panel w/ touch, i5 gets 1080p and no touch; i7 gets more RAM, i5 gets less; and so on.

[1] http://www.dell.com/ie/p/xps-13-9343-laptop/pd

[2] http://anandtech.com/show/9483/intel-skylake-review-6700k-66...

Dell probably does that so that they can quickly benefit from the following price drop. Most of their market will not even know what the latest processor is, anyway.

The mobile i5, at least he dual-core U-series, do have hyper-threading.

I would hope everyone would feature USB-C with their Skylake processors. There's no reason not to.

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