DDR3 speed, Altera vs Xilinx

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I get the impression that Altera is in the lead when it comes to speed on
DDR[3] interfaces. Can anyone confirm/deny this?

Altera claims to be able to clock a 64/72bit wide DDR3 at 533Mhz on the
StratixIII: http://www.altera.com/b/stratixiii-ddr3-video.html
For Xilinx, the fastest reference design I can find is 32bit wide DDR3 at
400Mhz for the Virtex5. Can Virtex4 do better?

So far, it looks to me like Altera did a KO on Xilinx when it comes to DDR3.
Please tell me I'm wrong, Id hate to switch tools :p
(and I need hard facts, not sales numbers)




Re: DDR3 speed, Altera vs Xilinx
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no, V4 can not do better
.

KO? did you count 10? :)

Antti

PS even DDR2 designs at 200MHz is not trivial for V4/V5, I would be
very careful before trying some Xilinx chip at memory clock above what
Xilinx itself claims. It doesnt mean that is not doable of course.
Already V4 slowest speed grade FPGA fabric can have signals as high as
1GHz (my own test measurements!) for very short distances, so 533
should not be impossible for V5 highest speed grade. But its not the
fabric or I/O speed alone that is needed for the successful
implementation.

PPS Xilinx are you KO?
1,2,3... tick-tock clock is ticking



Re: DDR3 speed, Altera vs Xilinx
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Altera has dedicated logic for source synchronous clocking for memories,
that might make the difference. But be aware that that dedicated logic
also creates more restrictions to pin placement and can waste big
amounts of pins if you use many IO-voltages. In Xilinx V4/V5 the pin
placement is sometimes easier to do. IO-structure is always a compromise
between speed and flexibility.

--Kim

Re: DDR3 speed, Altera vs Xilinx
Morten,

We chose different paths:  Altera used hardened logic to get their
speed, where we chose to stay general, and use any pins/any fabric/any
standard.

We have DDR3 designs that are also working at 533 MHz.

Best to sit down and talk with your FAE on the subject.

There are many other factors to consider (not he least of which is we
are in full production on Virtex 5 LX, LXT, SXT, and they are just now
in ES on on few parts, with S3 GX canceled completely).

Even though Altera has some really mean, cool, and neat power point
presentations, we basically have no competition whatsoever at 65nm at
the high end (as you can't ship power point in your systems).

Austin

Re: DDR3 speed, Altera vs Xilinx
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LOL, eh, think there is only one tool we need:

"powerpoint to silicon compiler" ;)

Antti

PS 553 MHz DDR3 without hardened io and general purpose FPGA is nice
achievment

Re: DDR3 speed, Altera vs Xilinx

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But is it worth something in a real application or is it just 'cool'?
When reading Xilinx memory interface application notes I get the
feeling the cool factor (to get numbers to put in nice powerpoint
presentations) is often more important than practical use. 533 MHz is
pushing the limits on a Xilinx device but with dedicated I/O logic
(like fast local clock paths for DQS) it would be a breeze to design.
The way Xilinx works they say it can be done, but every more
complicated interface like PCI, DDRx, PCI Express, serial ata, etc,
etc is suddenly extremely difficult and should be left to the
professionals. It is like Ford saying their cars are great and better
than the rest, but in the real world you'll find you need 3 arms to
drive around.

A lot can be said about Altera, but almost every hobbiest FPGA user in
the world is using Altera devices. This certainly says something about
the ease of use of Altera parts and software.

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

Re: DDR3 speed, Altera vs Xilinx
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<snip>

I'd love to see your reference  ;-)
Or perhaps you know most of the hobbyists personally?

I like seeing hobbyists use the tools and parts that are best for
their activities whatever they may be.

- John_H

Re: DDR3 speed, Altera vs Xilinx
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almost ROTFL :)

1. all assumptions are assumed false..

well, there is some trend towards "altera-love" for the hobby use:

1) C1 reconfigurable computer -> ACEX-1K
2) japanese MSX computer -> Cyclone
3) TREX-C1 -> Cyclone

so some retro-hobby folks defenetly prefer Altera,
but that of course doesnt mean "almost every hobby user"

Antti

Re: DDR3 speed, Altera vs Xilinx
...

~984 hits for - Altera FPGA Hobby use - on google (no quotes).

~27,200 hits for - Xilinx FPGA Hobby use - on google (no quotes).

Not that "Hobby Use" is a big line item on the financial report, but...

As much as this is not a scientific survey, it is still pretty telling!

Oh yes, those hobbiests are just swarming all over those Altera parts.

Austin

Re: DDR3 speed, Altera vs Xilinx
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Austin,

your "hit comparison" is example of bad(brilliant) use of google for
statistics.

the 27000 to 990 is not true ration of xilinx:hobby vs altera:hobby

fact is there are no commercial retro-compurers ever built on Xilinx
devices, all are Altera based, this has surprised my sometimes, as it
really made me also think that hobby people (at least some) prefer
Altera

of course on reason for hobby-altera is the fact that LARGEST non-BGA
FPGA device is made by Altera. And that latest Xilinx low cost family
is not all available in non-BGA packages (i dont count the tiny S3A-50
at all, as it just so tiny)

Antti

Re: DDR3 speed, Altera vs Xilinx
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:) you say it.
well, if you have found ONE commercially produced retro computing
platform with Xilinx i would like the reference.

yes, of course, Trenz has retro-computing BASEBOARD (for xilinx
modules) but this does not count.
there is also the board from the xilinx guy, but that was never
commercially produced.

besides those I do not know any.

ah, now i understand; yes there are may REAL hobby retro projects
implemented for Xilinx FPGA

but I was talking about BOARDS designed for retro-computing as MAIN
purpose.
from those 3 are made with xilinx.

burched tried something, but it was genpurpose xilinx board + modules
combined and named as retro computer, so it doesnt count as well.

but still, if any one is aware of ONE SINGLE commercially produced
device for retrocomputing made with Xilinx FPGA I am all ears..

Antti


















Re: DDR3 speed, Altera vs Xilinx
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sorry my typo, above must read:

from those 3 are made with altera!

typing too fast. should maybe follow some advice given long time ago:
"cut the 37 fingers" (then it types better)

Antti





Re: DDR3 speed, Altera vs Xilinx

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It's not a "market" it's a marketing/advertising opportunity.  If I
were A or X I think I'd hire a full-time product-evangelist engineering
position and task them with getting products into the hands of new
users and supporting the "hobbyist" people.  Make a $10 battery
powered demo board with some blinkenlights and give them away to
pretty much anyone who wants one.  Send someone to the Maker Fair
and similar venues with a few hundred giveaway boards and CDs with
WebPack etc.  Sounds like pretty cheap advertising to me.

Austin's two paragraphs above only make sense together if he believes
that no hobbyist ever turns into (or even communicates with) a
professional FPGA-using engineer.  Otherwise half of the game is
getting more mindshare than the competition and having people feel
good about your brand and tools when someday someone says "hey,
maybe we should use an FPGA for this application".

There's a lot of profit in having your brand be the first one that
people encounter.

G.

Re: DDR3 speed, Altera vs Xilinx
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Hence the Xilinx University Programme.
Certainly, in the UK both Xilinx and Mentor FPGA tools are widely used
across Universities.
If this isn't promotion to potential professionals then I don't know
what is.
For the hobbyist, a low-end Digilent board and ISE WebPack never broke
the bank.

As to implementing DDRx interfaces, having put a DDR2 interface on a
V5LX50 device last year, I am not sure that the flexibility of the
underlying structure is necessarily worthwhile the hassle for the end
user.
The general purpose flexibility of the logic is made irrelevant by the
number of different pinouts of Xilinx devices in a series.
The main gain is for the silicon vendor in being able to have fewer
product variants and save real-estate on hard implementations of
features that only a few customers want.

Andrew


Re: DDR3 speed, Altera vs Xilinx

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And here you guys are making a serious mistake. People tend to
continue use the devices they learned work with at home or at school.
I see this regulary with interns. If they learned to work with FPGA's
from Altera, they will look at Altera first if they need something. So
if Altera fits the bill, Altera wins a design-in into a product.

I see this happen every time with interns. Ofcourse Altera can be
replaced by any manufacturer's name.

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

Re: DDR3 speed, Altera vs Xilinx
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You are so right. It's sometimes even surprising how much we all
"try to play with known toys", I am trying to get rid of my
electronics
junkyard, so I asked on german forums if someone wants to look
and grab things of interest. So one student did come, and all he
looked for was PIC stuff, he say he know that, and thats it.
No Atmel chip, no FPGA thing, nothing just the things he had
used before.

I used PIC when PIC15C54 was "hot", as they had almost
no competition. I changed to AVR as they are better.

But Microchip is still VERY succesful selling his PICs
that are really bad architecture, mainly because of their
marketing. Every **** student wants PIC, and they will
use it in the everyday work later on too. No matter
that there are no advantages of using PIC. Its just
the routine, and "familiar", it will be used if it fits.

So the "educational" and hobby, etc.. is of importance.
Also for FPGA vendors i would say. Without the "edu+hobby"
popularity of the PIC's Microchip could not have success.

2eurocents
Antti






Re: DDR3 speed, Altera vs Xilinx
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..

...

Complex parts like complex FPGA/CPLD need complex toolchain. You have to
manage these tools for a long time, if you once decide to roll out some
product with this chain. So changing FPGA needs changing the chain and
careing for both, so you think double before changing...

--
Uwe Bonnes                 snipped-for-privacy@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
We've slightly trimmed the long signature. Click to see the full one.
Re: DDR3 speed, Altera vs Xilinx
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Better for some things, not for everything.  I had several designs using
PICs for which AVRs would not have been fast enough.  (There are faster
AVRs now, but there are faster PICs too.)

If one were to pick parts purely on technical merit of the parts, both
would win some designs.  However, there's also the tradeoff of saving
development time by using parts and tools with which one is already
experienced.

Re: DDR3 speed, Altera vs Xilinx
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yes agreed, at the beginning where it was PIC16C84 vs AT90S1200
it was clear win for AVR, but microchip has no so many new chips
that they defenetly win designs where AVR do not fit because of
lack of functions or speed or other details.

well both PIC and AVRs are no loosing against 32 bit low cost MCUs
eh, I am writing just now "My first STM32" book ;) a ARM that cost
less 3 usd runs at 72mhz (also from internal osc!) and has USB
and 64KByte flash.. why think of 8 bit micros for designs where
the 3 usd price is acceptable? sure for sub 1 usd prices 8 bit
MCUs are considered.

Antti








Re: DDR3 speed, Altera vs Xilinx

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Just look around in electronics forums for beginners and start
counting.

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

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