16GB RAM Xserve Graphic?

[MacRumors]

Curiously, Apple's web server hosts this image -- which claims 16GB of ECC RAM in the new G5 Xserve... while the "official" image and specs list only 8GB possible.

[GotherThanThou]

is that possible, with two G5's?

[backspinner]

Looks like a lot last minute changes... First no 2.3GHz, now 16GB to 8GB downscaling.

[zaphoyd]

Are there 2GB chips available? Do you think they were planning on make 2GB chips available and could not get them in stock? They certainly wouldn't add 8 more slots for 1GB chips... Maybe 2Gb chips are available, and you can have 16GB, just like my iMac whose ram max is 128MB has 288MB.

[rweidmann]

I think the issue is availability of 2GB EEC modules. Didn't Rubinstein in some interview even say that the Powermac G5 does support these modules once they come out. I think that they are simply not out or too expensive.

Apple has often understated the capabilities of memory controllers due to non-availability of high capacity memory modules.

[Skiniftz]

I found this ages ago. ...and in fact I submitted it here on the same day...

[Pismo]

If 2GB Dimms existed, can the Xserve and OS X Server support that much RAM? Those Dimms would probably cost $1000 or more each!

[metfoo]

phil s. stated they were waiting for 2 GB modules to be cheap enough to use. 16GB will come, mjust not today. the 8gb barrier is just temp barrier

[BenRoethig]

Originally posted by metfoo
phil s. stated they were waiting for 2 GB modules to be cheap enough to use. 16GB will come, mjust not today. the 8gb barrier is just temp barrier

True. Both the dual PMG5 and the Xserves can support 2gb DIMMs ofr up to 16gb. However, they are very rare and unaffordable for most.

[0 and A ai]

Originally posted by zaphoyd
Are there 2GB chips available? Do you think they were planning on make 2GB chips available and could not get them in stock? They certainly wouldn't add 8 more slots for 1GB chips... Maybe 2Gb chips are available, and you can have 16GB, just like my iMac whose ram max is 128MB has 288MB.

what the heck imac do you have.

[yoman]

16GB!! I can't imagine what would 16GB RAM be used for. That's almost as much as my hard drive space: 18.62GB. Wow! Good on apple for being forward looking in ram. Makes the xServe more future proof.

[Dave K]

Crucial began offering 2 GB PC3200 ECC DIMMS sometime last month.

IIRC, the developers notes on the G5 PowerMacs noted that, while the tech sheet says 8 GB max, the memory controller always supported 16 GB should 2GB DIMMS be available. Given that Apple tends to reuse chipsets between machines, I would be very surprised if the xServe wasn't the same.

Edit: Not reading Crucial specs fully.

[wymer100]

I also remember Phil S. mentioning that the xServes would go up to 16Gb of RAM, but the 2Gb sticks were just too expensive right now. Crucial has a 2Gb stick for US$999. Ouch, considering that you have to buy in pairs. However, a 2Gb kit (presumably 2x1Gb) from Kingston is something like US$1117.

[stingerman]

If you need a 16GB database server, 999 is pretty cheap compared to the alternatives. This definitely puts Apple at the very high end of cluster-able servers.

[Chryx]

Originally posted by Dave K
Crucial began offering 2 GB PC3200 ECC DIMMS sometime last month.

IIRC, the developers notes on the G5 PowerMacs noted that, while the tech sheet says 8 GB max, the memory controller always supported 16 GB should 2GB DIMMS be available. Given that Apple tends to reuse chipsets between machines, I would be very surprised if the xServe wasn't the same.

Edit: Not reading Crucial specs fully.

Those Crucial Dimms are registered, which to my knowledge won't work in the Xserve or (or the Powermac)

[tny]

Originally posted by yoman
16GB!! I can't imagine what would 16GB RAM be used for. That's almost as much as my hard drive space: 18.62GB. Wow! Good on apple for being forward looking in ram. Makes the xServe more future proof.

I can imagine a use for that much ram.

[pgwalsh]

Originally posted by tny
I can imagine a use for that much ram.

That was an interesting read and I think we could have an interesting thread topic on this.

I'm thinking writeable rom chips for OS and certain applications like PhotoShop.. That would be much more stable and wicked fast.

[jamilecrire]

Originally posted by yoman
16GB!! I can't imagine what would 16GB RAM be used for. That's almost as much as my hard drive space: 18.62GB. Wow! Good on apple for being forward looking in ram. Makes the xServe more future proof.

Enterprise level database server. I keep bugging Oracle about making their release "supported" but it looks like I'll be going with Sybase instead. I'm looking to migrate my companies application from a dual setup (linux/jsp/oracle & windows/asp/sql server) to one platform. Apple offers Tomcat with their Apache distribution so we'll be converting to OS X Server, JSP & Sybase Adaptive Server Enterprise (http://www.sybase.com/products/databaseservers/ase) instead of Oracle.

Oh to clarify, our database is around 13GB and running it in ram is better than off a hard drive (even if it is RAID 0 with redundant servers).

[nek]

Originally posted by wymer100
I also remember Phil S. mentioning that the xServes would go up to 16Gb of RAM, but the 2Gb sticks were just too expensive right now. Crucial has a 2Gb stick for US$999. Ouch, considering that you have to buy in pairs. However, a 2Gb kit (presumably 2x1Gb) from Kingston is something like US$1117.

It may seem expensive, but anyone who wants at least 4GB of RAM is better off getting 2 2GB DIMMs for $1998 instead of 4 1GB DIMMs for $2234 and then there is still lots of room for expansion.

[MrMacMan]

Price is an issue...

Apple can claim that it can go 16 GB Ram... but people will call them on it and apple would have to say 'buy these 2 GB sticks at $1000 a piece'... so yeah not practical to tell that to everyone.

It will happen when prices are lowered.

[ehurtley]

Originally posted by MrMacman
Price is an issue...

Apple can claim that it can go 16 GB Ram... but people will call them on it and apple would have to say 'buy these 2 GB sticks at $1000 a piece'... so yeah not practical to tell that to everyone.

It will happen when prices are lowered.

Except anyone who is even contemplating a server that needs 16GB of RAM is perfectly aware of the costs involved.

The other option would be 16 1GB DIMMs (at over $500 a piece, so just as bad.)

Trust me, in the server industry, high cost isn't something customers call manufacturers on. At least, with the commodity components. Now, if Apple themselves were trying to sell the 2GB DIMMs for $4000 a piece, that's another story.

[SiriusExcelsior]

i read somewhere that each 64-bit chip theoriotically supported up to 4TB (not typo) of ram... so 16gb of ram shouldn't be so much of a surprise...

this is of course assuming that such modules (512gb, 1tb, 2tb or 4 tb) were available....

[vitaboy]

Actually, a 64-bit processor can theoretically support 2^64 bytes of memory.

This is

1.845e+19 bytes
=1.801e+16 KB
=1.759e+13 MB
=1.718e+10 GB
=16,777,216 TB
=16,384 PB (petabyte)
=16 EB (exabytes)

In other words, a 64 bit processor can theoretically address more than 16 BILLION gigabytes of RAM.

By the way, I think I read the same article where the 4 TB figure was thrown around, but it was clearly a factual and mathematical error on the writer's part. 16 exabytes is millions of times more than a measly 4 terabyte system.

Even with Moore's Law, it will be quite a while before we start running into the theoretical limits of 64-bit memory addressing.

The reason why Apple is only stating 8 GB of RAM support (or 16 GB, which should happen once 2 GB EEC memory sticks are on the market) is for wholly practical reasons.

Even if it were possible to manufacture 1 terabyte memory sticks, the current technology for accessing that memory would be WAY too slow. For example, the G5 chips is a bandwidth monster compared to other chips on the market and it can move 6.4 GB per second in and out of the chip.

If you had a sever with a "measly" 1 TB of RAM, the G5 chip would take, oh, 160 seconds to go through the contents of the RAM completely at top theoretical speed. Never mind how long your coffee break will be waiting for the computer to go through 16 exabytes of RAM. We'll need totally fantastical technologies like holographic quantum mechanical memory or something.

So clearly, your memory bandwidth has to grow along with memory capacity, and so we probably won't see Macs move beyond 16 or 32 GB of RAM until a next-gen, higher bandwidth PowerPC chip comes along. G6 anyone?

[ehurtley]

Originally posted by vitaboy
Actually, a 64-bit processor can theoretically support 2^64 bytes of memory.
[math removed]
In other words, a 64 bit processor can theoretically address more than 16 BILLION gigabytes of RAM.

From what I remember, the PowerPC 970 processor itself only supports addressing up to 4TB of memory. This is a specific design choice/limitation of the IBM PowerPC 970 chip. Just as the PowerPC 601 was a 32-bit chip that supported only 2GB of RAM (even though 32-bit architectures can support 4GB.)

[vitaboy]

Originally posted by ehurtley
From what I remember, the PowerPC 970 processor itself only supports addressing up to 4TB of memory. This is a specific design choice/limitation of the IBM PowerPC 970 chip. Just as the PowerPC 601 was a 32-bit chip that supported only 2GB of RAM (even though 32-bit architectures can support 4GB.)

This may indeed be the case, since there is no practical way today to build a system with even a petabye of RAM and test it. But theoretically speaking, 2^64 is 16 exabytes, which is a pretty mind-boggling figure that's of Douglas Adams proportions.